A conchological manual

by G. B. Sowerby

1. Pyramidella. Pyramidal, with numerous whorls. Fig. 342.

2. Tornatella. Cylindrical, with few whorls. Fig. 343, 344.

3. Ringicula. Margin reflected. Fig. 540, 541.

PLICADOMUS. Sw. A sub-genus of Pupa, thus described: "spire moderate, regular and thick, but gradually conic; the tip obtuse; aperture perpendicular; inner lip wanting; outer lip semicircular; the margin dilated and reflected. P. sulcata, Chem. 135, f. 1231, 1232." Sw. p. 332.

PLICATED. (Plicatus, folded.) Applied to spiral plaits on the columella of some shells. Ex. Voluta, fig. 433. Also to the angular bendings in the margins of some bivalve shells. Ex. Dendostrea, fig. 181.

PLICATULA. Lam. (Plicatus, folded.) Fam. Pectenides, Lam. Sub-ostracea, Bl.—Descr. Irregular, sub-equivalve, sub-equilateral, attached by a small part of the surface of one valve, strongly plicated; umbones separated by a small, external ligamentary area; hinge with two cardinal teeth in each valve, two approximate in one valve, received between two distant in the other; cartilage placed between the cardinal teeth; muscular impressions one in each valve.—Obs. The cardinal teeth resembling those of Spondylus, distinguish this genus from others of the Lamarckian family Pectenides. Very few species are yet known, they are brought from the East and West Indies and the Philippine Islands. Fossil species are found in several of the supra-cretaceous beds. Fig. 178, P. gibbosa.

PNEUMOBRANCHIA. Lam. The second section of the order Gasteropoda, Lam. containing the family Limacinea, fig. 256 to 263.

PODOPSIS. Lam. This genus appears to have been described from specimens of a species of Spondylus, with the triangular disc broken out, so as to present a similarly shaped foramen, which was supposed to afford a passage for a large byssus.

POLINICES. Montf. A genus composed of Natica Mammilla, and other similar species, with mammillated spires, and the umbilicus filled with enamel. Fig. 327.

POLLIA. Gray. Tritonidea, Sw. The name given by Gray was pre-occupied by a genus of Lepidopterous Insects.

POLLICIPES. Leach. (Pollex, a thumb's breadth; pes, a foot.) Order. Pedunculated Cirripedes, Lam.—Descr. Conical, compressed, consisting of numerous valves, mostly in pairs, three or four pairs forming the principal part of the shell, and surrounded at the base by two or three rows of smaller valves, supported on a scaly, short pedicle.—Obs. This description will be found to exclude Scalpellum, and Smilium, the valves of which are more equal. The P. Mitellus, Auct. (fig. 37*), has been separated as a genus under the name of Mitellus by some authors, and it is certainly very different from P. polymerus, fig. 37, and P. cornucopia.

POLLONTES. Montf. Miliola, Bl. A genus of microscopic Foraminifera.

POLYBRANCHIATA. Bl. (Πολυς, polus, many; branchiæ, gills.) The fifth family of the order Lamellibranchiata, Bl. containing the genera Arca, Pectunculus and Nucula, which have a series of small teeth on the hinge.

POLYDONTES. Montf. (Πολυς, polus, many; οδος, odos, tooth.) A species of Helix, shaped like Carocolla, and having a number of teeth in the aperture.

POLYGONAL. Many-sided.

POLYGONUM. Schum. (Πολυς, polus, many; γωνια, gonia, an angle.) A genus composed of species of Turbinella, Auct. which have large continuous costæ, so as to present the appearance of many-sided shells. T. polygonus, fig. 383. This generic name may be used to include all those species of Turbinella, Auct. which have very small folds on the columella.

POLYGYRA. Say. A genus of Heliciform shells, characterized by the large number of close set whorls, constituting the spire. Ex. P. Septemvolvus, fig. 275, 276.

POLYLEPAS. Bl. (Πολυς, polus, many; λεπας, lepas, rock.) Scalpellum, Auct.

POLYMORPHINA. D'Orb. A genus of microscopic Foraminifera.

POLYPHEMUS. Montf. A genus composed of species of Achatina, Auct. which have elongated apertures, short spires, and an undulation in the outer lip. P. Glans, fig. 288.

POLYPLAXIPHORA. Bl. The second class of the sub-type Malentozoa, Bl. containing the genus Chiton.

POLYSTOMELLA. Lam. A genus of microscopic Foraminifera.

POLYTHALAMACEA. Bl. (Πολυς, polus, many; Θαλαμος, thalamos, chambers.) The third order of Cephalophora, Bl. the shells of which are described as straight, more or less symmetrically convolute, divided into several chambers. The septa are sometimes, but not always, pierced by one or more siphons. This order is divided into the families, Orthocerata, Lituacea, Cristacea, Ammonacea, Nautilacea, Turbinacea, Turriculacea, all of which contain genera of chambered shells. De Blainville arranges these families according to the degree in which the spires revolve. The first being straight, as the Orthocerata, and the last being so closely coiled up, that the last whorl covers the rest, as in the Nautilacea.

POLYTHALAMIA. Lam. The first division of the order Cephalopoda, Lam. containing the following families of chambered shells, viz. Orthocerata, Lituacea, Cristacea, Sphærulacea, Radiolata, Nautilacea, Ammonacea. Fig. 463 to 484.

POLYTROPA. Sw. A genus of "Scolyminæ," Sw. thus described: "Bucciniform; but the base narrow, and ending in a straight and contracted, but rather short, channel; spire longer, or as long as the aperture; exterior folliculated, or tuberculated; inner lip flattened, as in Purpura; basal notch small, oblique; no internal channel; crispata. En. Méth. 419, f. 2. Chem. 187, f. 1802. Capilla, Pennant, pl. 72, f. 89, imbricata. Mart. 122. f. 1124. ? rugosa. Chem. f. 1473-4." Sw. p. 305.

POLYXENES. Montf. A genus of microscopic Foraminifera.

POMATIA. Gesner. (Gray, Syn. B. M. p. 133.) A genus of the family of "Cyclostomidæ," described as having "an elongated shell with reflexed lips, and a horny spiral operculum." Also a sub-genus of Snails, containing Helix pomatia, Auct. (Gray's Turton, p. 135.)

PORNUS. Humph. Ampullaria, Lam.

PORCELLANA. Adanson. Marginella, Auct.

PORODRAGUS. Montf. A genus composed of species of Belemnites, placed by De Blainville in the section characterized as swelled near the apex, and straightened towards the base.

POSIDONIA. Brong. A genus formed on the cast of a bivalve shell, common on schists from Dillemberg.

POSTERIOR. (After, behind.) The posterior or hinder part of a bivalve shell, is that in which the siphonal tube of the animal is placed. It is known in the shell, by the direction of the curve in the umbones, which is from the posterior towards the anterior; also by the ligament, which is always placed on the posterior part of the hinge, when it exists only on one side of the umbones; and by the sinus (when there is one) in the palleal impression, which is always near the posterior muscular impression. In some shells, however, it is very difficult for a learner to trace these marks; such bivalves, for instance, as have the ligament spread out on both sides of the umbones; such as are nearly symmetrical, and have the umbones consequently straight, and a single muscular impression near the centre of the valve. The Brachiopodous bivalves have a different position, with relation to the animal, from the other bivalves, so that the hinge line is the posterior extremity, and the part where the valves open, is the anterior. The posterior extremity of the aperture of a spiral univalve shell, is that nearest to the spire. In patelliform shells the anterior and posterior extremities are distinguished by the muscular impression, which is annular, enclosing a central disc in the inner surface of the shell, excepting where it is interrupted by the place where the head of the animal lies, which of course is anterior. The posterior is marked p. in fig. 119, and 387. See Anterior.

POSTERO-BASAL MARGIN of a bivalve shell is the posterior side of the margin opposite the hinge.

POSTERO-DORSAL MARGIN is the posterior side of the hinge.

POTAMIS or POTAMIDES. Brong. A genus of fresh-water shells resembling Cerithium in the characters of the aperture, but which may be known from that genus by the thick, horny epidermis with which they are coated. P. muricata, fig. 377. (Cerithium, Sow.) We think that these shells should be placed near Melania.

POTAMOMYA. A genus of shells resembling Corbula, in every respect except that of being inhabitants of fresh-water. Fig. 498, 499, represents one of these fresh-water Corbulæ.

POTAMOPHILA. Sow. (Ποταμις, potamis, river; φιλιος, philios, choice.) "Conques fluviatiles," Lam.—Descr. Thick, equivalve, inequilateral, trigonal, covered with a greenish brown, smooth, horny epidermis; hinge thickened, broad, with one central, notched cardinal tooth in one valve, and two in the other, with indistinct lateral teeth; ligament large, supported on prominent fulcra; muscular impressions two in each valve, sub-orbicular.—Obs. The name given to this shell refers to its place of abode, being found in rivers. It is the Venus sub-viridis of some authors, although being a fresh-water shell, and having an incrassated hinge, and a smooth, thick epidermis, it is most distinct from that genus. It is described by Bowdich under the name Megadesma, on account of its large ligament, and by Lamarck under that of Galathæa, a name previously used by him for a genus of Crustacea. P. radiata, fig. 115. Megadesma appears to be the preferable name, since it has the right of priority over Potamophila. It is found in Africa.

PRIAMUS. A genus composed of Achatina Priamus, Lam. Buccinum Stercus—Pulicum, Chemn. Conch. 9. t. 120. f. 1026-7. This shell is ascertained to belong to a marine mollusc, having a horny operculum, and therefore is justly considered to form a distinct genus, allied to the Buccina and Struthiolariæ. Fig. 545.

PRISODON. Schum. Hyria, &c. Auct. Fig. 144.

PRODUCED. (Productus, prominent.) A term applied to the spire of univalve shells, or to any other prominent portion.

PRODUCTA. Sow. (Productus, produced.) Fam. Brachiopoda, Lam.—Descr. Equilateral, inequivalve, thick, striated; one valve generally convex, with the margin inflected, produced; the other valve flat, or slightly convex, with the margin reflected; hinge rectilinear, transverse.—Obs. The peculiarity of this genus, from which it derives its name, is the manner in which the anterior margins of the valves are drawn out and overwrap each other. The genus is only known in a fossil state. Species occur in Mountain Limestone, and Transition Limestone of older date. P. depressa, fig. 206.

PROSERPINA. Gray? Fig. 274, represents a small shell belonging to the Helix tribe, to which it is believed, Mr. Gray has applied the name Proserpina nitida. We do not know how the genus is defined.

PROTO. Defr. A fossil shell resembling Turritella, but having a spiral band reaching to the centre of each valve. P. terebralis, Bl.

PSAMMOBIA. Lam. Fam. Nymphacea, Lam.—Descr. Transverse, oblong, slightly gaping at both ends; hinge with two cardinal teeth in one valve, one in the other; ligament supported upon a prominent fulcrum; muscular impressions two in each valve, sub-orbicular, distant; palleal impression with a large sinus; epidermis thin.—Obs. The genus thus described includes Psammotæa of Lamarck, which, according to him, only differs in the number of teeth, and which he says are but "Psammobies dégenerées." The difference appears to be accidental. This genus differs from Tellina in not having a posterior fold in the margin. Fig. 100. The species are found in temperate and tropical climates.

PSAMMOCOLA. Bl. (ψαμμος, psammos, sand; cola, an inhabitant.) A name given by De Blainville to shells of the genus Psammobia, including Psammotæa of Lamarck.

PSAMMOTÆA. See Lam. Psammobia.

PSEUDOLIVA. Sw. A genus of "Eburninæ," Sw. thus described: "Shell thick, oval, oliviform, ventricose; spire very short, acute; base with two parallel grooves, one of which forms a notch at the base of the outer lip; suture slightly channelled; inner lip very thick, and turning inwards; aperture with an internal canal. Connects the Turbinellidæ with the Volutidæ. P. plumbea, Chem. 188. f. 1806, 1807." Sw. p. 306.

PSILOSTOMATA. Bl. The third family of Aporobranchiata, Bl. containing no genera of shells.

PTEROCERAS. Auct. (Πτερον, pteron, a wing; κερας, ceras, horn.) Fam. Ailées, Lam.—Descr. Turrited, oval, ventricose, thick, tuberculated; spire short; aperture oval, terminating in a lengthened canal at both extremities; outer lip thickened, expanded, produced into horn-shaped, hollow, thickened spires, with an anterior sinus apart from the canal.—Obs. This genus, containing the shells commonly called Devil's Claws, Gouty Scorpions, Spiders, &c. is distinguished from Strombus by the digitations of the outer lip. No fossil species are known. Fig. 405, P. aurantiaca.

PTEROCYCLOS. Benson. Syn. B. M. p. 133. A genus formed of species of Cyclostoma, Auct. which have "a groove or hole at the hinder part of the mouth."

PTEROPODA. Lam. (Πτερον, pteron, a wing; πους, pous, a foot.) The first order of the class Mollusca, Lam. consisting of molluscs whose organs of locomotion consist of a pair of wing-shaped fins. This order contains the genera Hyalæa, Clio, Cleodora, Spiratella, Cymbulia, and Pneumoderma. To which may be added other genera enumerated in explanation of figures 220 to 226. They may be thus distinguished.

1. Atlanta. Shaped like Nautilus, symmetrical. Fig. 220.

2. Spiratella. Spiral, not symmetrical. Fig. 224.

3. Creseis. Straight, thorn-shaped. Fig. 222.

4. Vaginula. Straight, widened in the centre; apex pointed. Fig. 225.

5. Cuvieria. The same; apex blunt. Fig. 223.

6. Cleodora. Aperture with three spines; apex recurved. Fig. 221.

7. Hyalæa. Vaulted, open extremity, three-cornered; apex tridentate. Fig. 226.

PTEROPODA. Bl. The second family of Nucleobranchiata, Bl. the shells of which are described as symmetrical, extremely thin, transparent, longitudinally enrolled, either forwards or backwards. The animals are remarkable for a pair of broad, flat, natatory organs or membranaceous fins, from which the family derives its name. It contains, in the system of De Blainville, the genera Atlanta, Spiratella, and Argonauta, to which may probably be added Pharetrium, König; Entalis, Defrance.

PULLASTRA. Sow. Fam. Conques Marines, Lam.—Descr. Equivalve, ovate or oblong, transverse, inequilateral; hinge with three diverging cardinal teeth in each valve, notched at the terminations; muscular impressions two in each valve; palleal impression having a large sinus; ligament external, partly hidden by the dorsal margin.—Obs. This genus includes the Venerirupes of Lamarck, and several species of his Veneres, they are found in the sand on the shores of temperate and tropical climates. Fig. 120, P. textile.

PULMONOBRANCHIATA. Bl. The first order of the first section of Paracephalophora monoica, containing the families Limnacea, Auriculacea, and Limacinea.

PULVINITES. Defr. (Pulvinus, a cushion.) Fam. Malleacea, Lam.—Descr. Sub-equivalve, inequilateral, compressed, thin, slightly gaping posteriorly; one valve flat, the other rather concave; hinge linear, short, divided into perpendicular grooves; muscular impressions two, one sub-central, the other above it, nearer the hinge.—Obs. This fossil shell is imperfectly known, and it is difficult to give a sufficient reason for separating it from Perna. It comes from the Baculite limestone of Normandy. Fig. 170, P. Adansonii.

PUNCTATED. (Punctatus, spotted or dotted.) For example, see Conus Nussatella. Fig. 460.

PUNCTICULIS. Sw. A sub-genus of "Coronaxis," Sw. (Conus) described in Swainson's Malacology, page 311.

PUNCTURELLA. Lowe. Cemoria, Leach.

PUPA. Auct. Fam. Colimacea, Lam.; Limacinea, Bl.—Descr. Cylindrical, generally ribbed; spire long, obtuse, composed of numerous slowly increasing whorls; aperture sub-quadrate, rounded anteriorly, entire; outer lip thickened; columella plaited.—Obs. This genus is composed of land shells very variable in form, differing from Bulinus in the numerous slowly increasing whorls of the spire, and in the plicæ on the columella, and from Clausilia in the want of a clausium. Britain, Southern Europe, East and West Indies, Mexico, &c. P. Uva. Fig. 291.

PUPELLA. Sw. A sub-genus of Clausilia. Lardn. Cyclop. Malac. p. 334.

PUPILLA. Leach. A sub-genus of Pupa, P. marginata, Auct. (Gray's Turton, p. 196.)

PUPINA. Vignard. Moulinsia, Grateloup. Fam. Colimacea, Lam.—Descr. Pupiform, sub-cylindrical; last whorl less than the preceding; surface brilliantly polished; suture of the spire enamelled; aperture circular; peritreme thickened; a notch at the base of the inner lip; operculum horny, spiral.—Obs. The species upon which this genus was originally founded, and described in the "Annal des Sciences Naturelles," tome 18, p. 439, (December 1829,) is a small pupiform shell, having nothing to distinguish it but the enamelled suture and the notch in the aperture; characters quite insufficient in themselves for the purpose of generic distinction; at the same time sufficient to lead M. De Ferussac to the suspicion of its having an operculum. The next species, described by Grateloup under the name of Moulinsia Nunezii, (Ann. Soc. Linn. Burd, Nov. 1840), presents more remarkable characters, having the spire turned backwards and the penultimate whorl disproportionately large. Seven additional species have been lately brought to this country from the Philippine Islands by Mr. Cuming. They will be described by the author in the Zoological Proceedings for 1841, and an illustrated monograph of the whole genus is published in the Thesaurus Conchyliorum, Part I, by the Author. It may be observed that in one of the new species, the notch in the peritreme almost disappears, leaving a very slight sinus. Fig. 524, 526, 527, 528.

PURPURA. Auct. ("The shell-fish from which purple is taken," Plin.) Fam. Purpurifera, Lam. Entomostomata, Bl.—Descr. Oval or oblong, thick; spire for the most part short, sometimes rather longer; external surface generally sulcated, granulated, tuberculated or muricated; aperture long, oval, somewhat dilated, emarginated anteriorly; outer lip crenated, acute; columella flattened; operculum horny, with the nucleus lateral, thin towards the columella.—Obs. True Purpuræ to be found in the Lamarckian genera Buccinum, Ricinula, and others. They may be generally distinguished by the flatness of the columellar lip, and by the short canal or emargination, which is not reflected or raised, as in Buccinum. The species are very numerous and very variable in form, inhabiting the seas of temperate and tropical climates. The animals secrete a purple liquor, which has been used advantageously for dyeing; the origin of the famous Tyrian dye. Fig. 414, P. persica.

PURPURIFERA. Lam. (Purpura, purple; fero, to carry.) A family belonging to the second section of Lamarck's order Trachelipoda, the shells of which are described as having a very short recurved, or ascending canal, or else only a notch between the inner and outer lips. The name Purpurifera has been given to the family because the animals which it includes, and particularly the genus Purpura, contain the colouring matter from which the ancients obtained the well known splendid purple. This family contains the following genera.

1. Cassis. Outer lip thick, reflected, denticulated, canal turned suddenly over the back; spire short; including Cassidea and Cypræcassis. Fig. 410 to 412.

2. Cassidaria. Canal turned gently upwards. Fig. 407, 408.

3. Oniscia. Inner lip granulated; canal short. Fig. 409.

4. Buccinum. Outer lip thickened not reflected; canal short; including Cyllene and Phos. Fig. 416, 421, 422, 425.

5. Nassa. The same, with a notch or tooth at the extremity of the columella; including Cyclops. Fig. 423, 424.

6. Dolium. Swelled, grooved spirally; outer lip not reflected. Fig. 420.

7. Purpura. Aperture large; columellar lip flat; including Tritonidea. Fig. 414, 415.

8. Monoceros. The same, with a tooth on the outer lip. Fig. 417.

9. Concholepas. Patelliform; aperture as large as the shell. Fig. 417.

10. Ricinula. Columellar and outer lips granulated, denticulated, outer lip digitated; including Tribulus. Fig. 413.

11. Trichotropis. Hairs on the epidermis, along the keels. Fig. 429.

12. Terebra. Elongated, with a spiral groove near the suture of the whorls. Fig. 428.

13. Bullia. Short; aperture wide; outer lip marginated. Fig. 427.

14. Eburna. Like Buccinum, but the outer lip not thickened. Fig. 426.

15. Harpa. With varices at regular intervals. Fig. 419.

PUSIA. Sw. A sub-genus of Tiara (Mitra.) (Sw. Malac. p. 320.)

PUSIODON. Sw. A genus of "Lucerninæ," Sw. (Helix) thus described: "Shell flattened, smooth; the body-whorl large, and much dilated at the aperture; spire small, flat, of three or four contracted whorls; aperture very oblique, sinuated, or obsoletely toothed at the base of the outer lip, which is spreading and sub-reflected; inner lip obsolete; umbilicus open. Zonaria Chemn. 132. f. 1188. auriculata Zool. Ill. I. pl. 6." Sw. Malac. p. 330.

PUSIOSTOMA. Sw. A genus of the family "Columbellinæ." Sw. Thus described: "general form of Columbella, but the outer lip is only toothed in the middle, where it is greatly thickened; inner lip convex between the granular teeth; punctata, E. M. 374. f. 4. mendicaria, 375. f. 10. turturina, 314. f. 2. fulgurans. Lam." Sw. Malac. p. 313.

PUSTULARIA. Sw. A genus of "Cypræinæ," Sw. thus described: "Shell generally marked by elevated pustules; aperture narrow and linear; the extremities more or less produced; the teeth continued beyond, and frequently forming elevated striæ across the lips. P. Cicercula, P. Globulus." Sw. Malac. p. 324.

PYGMÆA. Humph. Columbella, Auct.

PYLORIDEA. Bl. The ninth family of the order Lamellibranchiata, Bl. the shells of which are described as nearly always regular, rarely otherwise, nearly always equivalve, gaping at both extremities; hinge incomplete, the teeth becoming gradually obsolete; two distinct muscular impressions; palleal impression very flexuous posteriorly. This family is divided into: Section 1. Ligament internal; Pandora, Thracia, Anatina, Mya, Lutricola. Section 2. Ligament external; Psammocola, Soletellina, Solen, Sanguinolaria, Solenocurtus, Solenimya, Panopæa, Glycimeris, Saxicava, Byssomya, Rhomboides, Hiatella, Gastrochæna, Clavagella, Aspergillum.

PYRAMIDAL. (Pyramidalis.) Resembling a pyramid in form. Ex. Cerithium Telescopium, fig. 378.

PYRAMIDELLA. Lam. (A little pyramid.) Fam. Plicacea, Lam. Auriculacea, Bl.—Descr. Pyramidal, smooth, polished; spire long, pointed, composed of numerous whorls; aperture small, modified by the last whorl, rounded anteriorly; outer lip slightly expanded; columella tortuous, with several folds. This is a genus of small, polished, marine shells. Pyramidella Terebellum, fig. 342.

PYRAZUS. Montf. Potamis, Brongniart.

PYRELLA. Sw. A genus consisting of Turbinella Spirilla, Auct. and similar species, having a long channel, a pyriform outline, and one strong plait at the base of the columella, the apex of the spire is enlarged. P. Spirillus, fig. 384. (The proper term would be Spirilla.)

PYRIFORM. (Pyrum, a pear; forma, shape.) Shaped like a pear, i. e. large and rounding at one end, and gradually tapering at the other. Ex. Pyrula, fig. 390.

PYRGO. Defr. A genus of microscopic Foraminifera.

PYRGOMA. Auct. (Πυργος, pyrgus, a tower.) Order, Sessile Cirripedes, Lam.—Descr. Composed of a single conical, hollow paries, with a small aperture closed by an operculum of four valves, and supported upon a cup-shaped base.—Obs. The genera into which Leach has divided this genus are Pyrgoma, Adna, and Megatrema; his genera Nobia and Savignium differ in having but two valves for the operculum. Pyrgoma differs from Creusia in having the body of the shell, i. e. the parietal cone, simple, not divided into valves. Fig. 31.

PYRGOPOLON. De Montfort's figure of this genus appears as if it had been drawn from the nucleus of a Belemnite.

PYRULA. Auct. (A little pear.) Fam. Canalifera, Lam. Siphonostomata, Bl.—Descr. Thin, oblong, pyriform, ventricose towards the spire, gradually tapering towards the anterior of the aperture, spire short, consisting of few volutions; aperture wide, terminating in a long, narrow, open, canal; columella smooth, elegantly tortuous.—Obs. The above description includes all the true Fig shells, which present a most graceful form; the contour partaking of the peculiar curve, called by painters the line of beauty. P. Ficus, fig. 390.

PYRUM. Humph. Pyrula, Lam.

QUADRATE. (Quadratus.) Square, applied when the outline of shells is formed by nearly straight lines meeting at right angles.

QUADRILATERAL. Four-sided.

QUINQUELOCULINA. D'Orbigny. A genus of microscopic Foraminifera.

RADIATING. (Radians.) A term applied to the ribs, striæ, bands of colours, &c. when they meet in a point at the umbones of a bivalve shell, and spread out towards the ventral margin.—Ex. The bands of colour in Tellina radiata, fig. 105.

RADICATED. (Radix, a root.) Attached, and as it were rooted by means of a fibrous byssus.

RADIOLATA. Lam. A family belonging to the order Cephalopoda, Lam. The shells belonging to it are described as discoidal, with the spire central, and the chambers radiating from the centre to the circumference. This family contains the genera Rotalina, Lenticulina, and Placentula.

RADIOLITES. A genus belonging to the family of Rudistes, differing from Sphærulites, in having both the valves more conical.

RADIUS. Montf. A genus composed of Ovulum Volva, Auct. and other similar species, having a long attenuated canal at each extremity. Fig. 442.

RADIX. Montf. A genus composed of species of Limnæa, having a short spire and wide aperture.—Ex. L. aperta, fig. 309.

RAMIFIED. (Ramus, a branch.) Branched out.—Ex. The varices of some Murices, &c.

RAMPHIDOMA. Schum. Pollicipes, Leach.

RAMOSE. (Ramosus, branched.) Spread out into branches. Ex. Murex inflatus, fig. 395.

RANELLA. Auct. (Rana, a frog.) Fam. Canalifera, Lam. Siphonostomata, Bl.—Descr. Oval or oblong, depressed, thick, with two rows of continuous varices, skirting the outline, one on each side; spire rather short, pyramidal, acute, aperture oval, terminating in a canal at each extremity; outer lip thickened within, crenulated, or denticulated, forming an external varix; inner lip spread over a portion of the body whorl.—Obs. The shells composing this well-defined genus, are for the most part covered with tuberculations, and granulations, and from the colour and squat shape of some species, have been likened to frogs. The Ranellæ are mostly inhabitants of the East Indian seas. The few fossil species known, occur in the tertiary beds. The two continuous rows of varices skirting the spire, distinguish this genus from Triton, which it nearly approaches, and into which some species run by imperceptible gradations. Fig. 393, 394. Many new species were brought to this country by Mr. Cuming, and are represented in parts 84, 85, 88, 89, 92, 93, of the author's Conchological Illustrations.

RANGIA. Desmoulins. Gnathodon, Gray.

RAPANUS. Schum.? A genus consisting of species of Pyrula, Auct. which are thin, much inflated, with short canals. Fig. 389, P. papyracea.

RAPELLA. Sw. A genus of "Pyrulinæ," Sw. thus described: "Shell ventricose, generally thin, almost globose; the base suddenly contracted, and forming a short canal, the channel almost obsolete; umbilicus large, partly concealed by the inner lip. R. papyracea. En. Méth. 436, f. 1." Sw. p. 307. Rapanus, Schum. Fig. 389.

RAPHANISTER. Montf. A species of madrepore, described as a shell.

RAPUM. Humph. Turbinella, Lam.

RAZOR SHELL. A common name by which shells of the genus Solen, are known in the market.

RECTILINEAR. (Rectus, right; linea, a line.) In a straight line. Ex. The hinge of Byssoarca Noæ, fig. 132.

RECURVED. (Re, back; curvo, to bend.) Turned backwards; the term, when applied to symmetrical conical univalves, is used to signify that the apex is turned towards the posterior margin, as in Emarginula, fig. 241.

REFLECTED. (Reflected, to fold back.) Turned, or folded backwards. Ex. The edge of the outer lip in Bulinus, fig. 282, is reflected, while that of Cypræa, fig. 445 to 450, is inflected.

REMOTE. (Remotus, distant.) Remote lateral teeth in a bivalve shell, are those that are placed at a distance from the cardinal teeth. Ex. The lateral teeth of Aphrodita, (fig. 123.) are remote; those of Donax, (fig. 108) are near.

RENIELLA. Sw. A sub-genus of Malleus. Lardn. Cyclop. Malac. p. 886. Gray states it to be only a distorted specimen of Vulsella, Syn. B. M. p. 145.

RENIFORM. (Ren, a kidney; forma, shape.) Shaped like a kidney. Ex. The aperture of Ampullaria, fig. 318.

RENULINA. Lam. A genus of microscopic Foraminifera.

REOPHAX. Montf. A genus of microscopic Orthocerata, Bl.

REPENT. (Repens, creeping.) A term applied to those shells, which, being attached by the whole length of their shell, give the idea of creeping or crawling. Ex. Vermilia, fig. 7.

RETICULATED. (Reticulatus.) Resembling net-work.

RETIFERA. Bl. The first family of the order Cervicobranchiata, Bl. containing the genus Patella.

REVERSED or Sinistral Shells, are those in which the aperture is on the left side of the shell, while it is held with the mouth downwards, and towards the observer. Ex. Balea, fig. 296. Attached bivalves are said to be reversed, when the left valve is free, instead of the right; a circumstance which sometimes occurs in Chama and Ostrea.

RHEDA. Humph. Hyalæa, Lam.

RHINOCLAVIS. Sw. A genus of "Cerithinæ," Sw. thus described: "channel curved backwards, in an erect position; inner lip very thick, with a tumid margin; pillar generally with a central plait; operculum ear-shaped; lineatum. En. M. 443, fig. 3, Vertagus. Ib. f. 2, subulatum. Lam. No. 23, fasciatum. Mart. 157, f. 1481. obeliscus, En. Méth. 443, f. 4; aluco, Ib. f. 5, (Aberrant,) semi-granosum. Ib. 443, f. 1, asperum. Mart. 157, f. 1483."

RHINOCURUS. Montf. A genus of microscopic Foraminifera.

RHINODOMUS. Sw. A genus of "Scolyminæ," Sw. thus described: No internal groove; shell clavate; the spire longer than, or equal with the aperture; the whorls with ridges or longitudinal varices, and rendered hispid by transverse grooves; inner lip wanting; pillar with a terminal fold; aperture striated; outer lip with a basal sinus. R. senticosus, Chem. tab. 193. f. 1864-1866.

RHIZORUS. Montf. A genus described from a microscopic shell, appearing to be a cylindrical Bulla.

RHODOSTOMA. Sw. A sub-genus of "Turbininæ," Sw. p. 344.

RHOMBOIDAL. (ῥομβοειδος, rhomboeidus.) Having a rhombic form, i. e. four-sided; two sides meeting at acute, two at obtuse, angles. Conchologists are not very strict in the application of this term, for, indeed, a perfect rhomboidal figure could not be found among all the testaceous productions of the sea.

RHOMBOIDES. Bl. A genus described as resembling Byssomya in the shell, but differing in the animal. Mytilus rugosus, Gmelin. Hypogæa barbata, Poli.

RHOMBUS. Montf. (ῥομβος, rhombos, a rhomb.) A genus consisting of species of Conus, having a rhomboidal or quadrilateral form and a coronated spire. Ex. Conus nocturnus, fig. 459.

RICINULA. Lam. (Resembling the seed-vessel of the Ricinus.) Fam. Purpurifera, Lam. Entomostomata, Bl.—Descr. Sub-ovate, thick, tuberculated; spire short; aperture narrow, terminating anteriorly in a short canal; outer-lip thickened, denticulated within, digitated without; columellar lip spread over a portion of the body whorl, and granulated.—Obs. This interesting genus is composed of some neat little shells allied to Purpura, from which they are distinguished by the finger-like branching of the outer lip, and the granulations of the columella. Fig. 413, R. Horrida.

RIGHT. See Dextral.

RIMULA. Defr. A genus consisting of a minute species of Emarginula, Auct. which has a fissure near the margin, but not reaching it. R. Blainvillii, fig. 243.

RIMULINA. D'Orbigny. A genus of microscopic Foraminifera.

RINGICULA. Deshayes. A genus founded on Auricula ringens of Lamarck and several small fossils, resembling in some respects Pedipes of Adanson; they would belong to Tornatella, were it not for the lips being thickened and marginated, fig. 540, A. ringens.

RISSOA. Freminville. Fam. Ellipsostomata, Bl. Melaniana, Lam.—Descr. Oblong, turrited, acuminated; spire long, consisting of numerous whorls; aperture round or oval, pointed posteriorly, dilated anteriorly; outer lip slightly thickened, emarginated, operculum horny.—Obs. The Rissoæ are small white, marine shells, considered by some authors as resembling Melaniæ, but placed by Sowerby near the Scalariæ. They are principally from the shores of the Mediterranean, and are also very abundant on the British shores, as well as the East and West Indian. Fig. 346, R. reticulata.

ROBULUS. Montf. A genus of microscopic Foraminifera.

ROLLUS. Montf. A genus composed of Conus Geographus, Auct. fig. 462, and other species, rather cylindrical in form, and having a coronated spire.

ROSALINA. D'Orb. A genus of microscopic Foraminifera.

ROSTELLARIA. (From rostrum, a beak.) Fam. Alatæ, Lam. Siphonostomata, Bl.—Descr. Turrited, fusiform, thick, smooth or ribbed; aperture oval, terminating anteriorly in a long canal, posteriorly in a channel running up the spire; outer lip dilated, thickened, sometimes digitated, running up all or part of the spire, with a sinus near the anterior canal; inner lip smooth, spread over part of the body whorl and of the spire. The Red Sea and the Indian Ocean produce the few known species of this genus.—Obs. Hippochrenes is the name given by De Montfort, to those fossil species which have the outer lip simple and very much dilated. R. curvirostrum, fig. 412. Aporrhais is a name given to another proposed genus, composed of Rostellaria pes-pelecani, Auct. fig. 404. and similar species.

ROSTRATED. (From rostrum, a beak.) Having one or more protruding points, as Tellina rostrata.

ROTALIA. Lam. A genus of microscopic Foraminifera. The same as Rotalites of De Montfort.

ROTELLA. Lam. (A little wheel.) Fam. Turbinacea, Lam.—Descr. Orbicular, generally smooth, shining; spire conical, depressed, short; aperture subtrigonal; outer lip thin, angulated near the centre; inner lip spread over the surface of the whorls, forming a thickened disc. Operculum horny, orbicular, spiral, with numerous whorls.—Obs. The pretty little shells thus described are found in seas of tropical climates. They are distinguished from other genera of the family by their lenticular form and the orbicular callosity of the under surface. Fig. 357, R. vestiaria.

RUDISTES. Lam. A family of the order Conchifera Monomyaria, Lam. the shells of which are described as irregular, very inequivalve, without distinct umbones; the ligament, hinge and animal entirely unknown. The shells contained in this family may be thus distinguished.

1. Calceola. Large valve conical; attached by a flat space between the umbones, which form the extremities of the shell. Fig. 194.

2. Hippurites. Large valve cylindrical, with two internal lobes or varices. Fig. 198.

3. Sphærulites. Large valve attached, including Radiolites. Birostrites is proved to be the cast of a Sphærulites. Fig. 193, 196.

4. Hipponyx. Flat valve attached, upper valve conical. Fig. 199, 200.

RUDISTES. Bl. The second order of the class Acephalophora, Bl. containing the genera Sphærulites, Crania, Hippurites, Radiolites, Birostrites and Calceola.

RUDOLPHUS. Lam. Monoceros, Auct.

RUFOUS. Reddish brown.

RUGOSE. Rough, rugged.

RUPELLARIA. Fl. de Belvue. An unfigured shell placed by De Blainville in a division of the genus Venerirupis.

RUPICOLA. Fl. de Belvue. A shell described by De Blainville as an equivalve, terebrating species of Anatina. A. rupicola, Lam.

SABINEA. A genus of shells resembling small species of Littorina, as L. Ulvæ, &c. of our shores.

SADDLE OYSTER. Placuna Sella, so called on account of a resemblance in shape to a saddle; the part near the umbones being flat, and the ventral margins being turned up in a sort of fluting or peak.

SAGITTA. (An arrow.) An ancient name for Belemnites.

SALIENT. (Saliens.) Jutting out, prominent.

SALPACEA. Bl. The second family of the order Heterobranchiata, Bl. containing no genera of shells.

SANDALINA. Schum. Crepidulina, Lam. A genus of microscopic Foraminifera.

SANGUINOLARIA. Lam. (Sanguis, blood.) Fam. Nymphacea, Lam. Pyloridea, Bl.—Descr. Equivalve, inequilateral, transverse, sub-ovate, rounded anteriorly, sub-rostrate posteriorly, compressed, thin, covered with a shining epidermis, gaping at the sides; hinge with two cardinal teeth in each valve, and an external ligament supported upon a prominent fulcrum; muscular impressions two in each valve, lateral, irregular, palleal impressions with a large sinus.—Obs. This description is made to exclude some of Lamarck's species of Sanguinolaria, such as S. occidens, S. rugosa, which are Psammobiæ; and to include others which he has left out. The Sanguinolariæ are sub-rostrated posteriorly, while the Psammobiæ are sub-quadrate and have a posterior angle. Fig. 98, S. rosea. Sandy shores of tropical climates.

SARACENARIA. Defr. A genus of microscopic Foraminifera.

SAVIGNIUM. Leach. A genus of Sessile Cirripedes, described as composed of four valves soldered together, and a convex bivalve operculum; the ventral and posterior valve on each side being soldered together, in other respects resembling Pyrgoma. Fig. 30.

SAXICAVA. Fl. de Belvue. Journ. de Ph. an. 10. (Saxum, a stone; cava, a hollow.) Fam. Lithophagidæ, Lam. Pyloridea, Bl.—Descr. Transverse, irregular, generally oblong, inequilateral, sub-equivalve, gaping anteriorly; ligament external; muscular impressions two, lateral; palleal impression interrupted, not sinuated; hinge, when young with sometimes two or three minute, obtuse, generally indistinct, cardinal teeth; which become obsolete when full grown.—Obs. Several genera have been founded only upon the difference between the young and old shell of the same species of this genus. The Saxicavæ are found in the little hollows of rocks; in cavities on the backs of oysters, of roots of sea-weeds, &c. in northern and temperate climates. S. rugosa, fig. 94.

SCABRICULA. Sw. A sub-genus of Mitræ, consisting of species which have a roughened external surface, &c. Sw. Malac. p. 319.

SCABROUS. Rough.

SCALA. Klein. Scalaria, Auct.

SCALARIA. Auct. Fam. Scalariana, Lam. Cricostomata, Bl.—Descr. Turrited, oval or oblong; spire long, composed of rounded, sometimes separate whorls, surrounded by regular concentric ribs; aperture oval, peristome reflected continuous, entire.—Obs. The typical species of this genus, commonly called the Wentletrap, (S. pretiosa) is celebrated for the beautiful appearance caused by the numerous ribs encircling the whorls, and formerly produced an immense price in the market. It is brought from China. There are many smaller species, some of which are equally elegant. Fig. 351, S. Pallasii, Kiener.

SCALARIANA. Lam. A family belonging to the first section of the order Trachelipoda, Lam. The shells belonging to it are described as having the inner and outer lips continuous, without a canal, emargination, or other division. In this respect the family is stated to differ from the Turbinacea, and is therefore separated. The genera may be distinguished as follows:—

1. Vermetus. Irregularly twisted, like Serpula. Fig. 345.

2. Eulima. Pyramidal; apex contorted; including Bonellia. Fig. 347, 348.

3. Rissoa. Pyramidal, straight, consisting of few whorls. Fig. 346.

4. Scalaria. With external varices. Fig. 351.

5. Cirrus. Trochiform. Fig. 349.

6. Enomphalus. Orbicular. Fig. 350.

7. Delphinula. Few whorls, rapidly increasing. Fig. 352.

SCALLOP. The common name for shells of the genus Pecten, the larger species of which were worn by pilgrims to the Holy Land in the time of the Crusades.

SCALPELLUM. Leach. (A little knife or lancet.) Order, Pedunculated Cirripedes, Lam.—Descr. Flat, quadrated, acuminated, composed of thirteen valves, one dorsal, arcuated; one pair apicial, acuminated; one pair ventral; two pair lateral, small, sub-quadrate; pedicle scaly.—Obs. This genus and Smilium, are the only Pedunculated Cirripedes which have thirteen valves; in the latter genus, which we think should at any rate be united to this, the valves are somewhat differently placed, and the pedicle is said to be smooth. Fig. 35, Scalpellum vulgare. British.

SCAPHA. Klein. (A boat.) Navicella, Auct.

SCAPHANDER. Montf. Bulla lignaria, Auct. Fig. 251.

SCAPHELLA. Sw. A genus of the family "Volutinæ," Sw. thus described: "Shell smooth, almost polished; outer lip thickened internally; suture enamelled; lower plaits the smallest; apex of the spire various: 1. fusiformis. Sw. Bligh. Cat. 2. undulatus. Ex. Conch. pl. 27. 3. Junonia, Ex. Conch. pl. 33. 4. stromboides. 5. papillosa. Sw. Sow. gen." Sw. Malac. p. 318.

SCAPHITES. (A boat.) Fam. Ammonacea, Lam. and Bl.—Descr. Convolute, chambered, closely related to the Ammonites, from which it differs in the last whorl being eccentrically straightened, and lengthened, and again incurved towards the extremity. Only known in a fossil state. Fig. 481, S. æqualis.

SCAPHULA. Sw. A genus of "Olivinæ," Sw. thus described: "Spire very short, thick, obtuse, and not defined; aperture very wide, with only two or three oblique plaits at the base. Sw. patula, Sow. Tank. Cat. 2331. (b.)" (Sw. p. 322.)

SCARABUS. Montf. (Scarabæus, a kind of beetle.) Fam. Colimacea, Lam. Auriculacea, Fer.—Descr. Oval, somewhat compressed, smooth, with slightly raised varices; spire equal in length to the aperture, pointed, consisting of numerous whorls; aperture ovate, rounded anteriorly, pointed posteriorly, modified by the last whorl; outer lip sub-reflected, with several prominent folds on the inner edge; inner lip spread over a portion of the body whorls, with several prominent folds.—Obs. The shells of this genus are found like Auriculæ, in marshy places. C. imbrium is said to have been found on the tops of mountains, by Captain Freycinet. Fig. 299*, S. imbrium.

SCHIZODESMA. Gray. A genus composed of species of Mactra, Auct. with the ligament placed in an external slit. Fig. 8, M. Spengleri.

SCISSURELLA. D'Orbigny. (Scissus, cut.) Fam. Turbinacea, Lam.—Descr. Sub-globose, umbilicated, with a spiral groove terminating at the margin of the outer lip in a slit; spire short; aperture oval, modified by the last whorl; outer lip sharp, with a deep slit near the spire. Recent on the coasts of Britain; fossil in the Calcaire-grossièr.—Obs. This genus, consisting of small shells, is known from Pleurotomaria by the shortness of the spire; the latter genus being trochiform. Fig. 340, S. elatior.

SCOLYMUS. Sw. A genus of the family "Scolyminæ." Sw. (Turbinella) thus described: "Sub-fusiform, armed with foliated spines; spire shorter; pillar with distinct plaits in the middle." The species enumerated are, "cornigerus, pugillaris, Globulus, Rhinoceros, ceramicus, Capitellum, umbilicaris, mitis." Sw. Malac. p. 304.

SCORTIMUS. Montf. A genus of microscopic Foraminifera.

SCROBICULARIA. Schum. Species of Lutraria, Act. of a rounded shape. Ligula, Leach.

SCROBICULATED. (Scrobiculus, a little ditch or furrow.) Having small ditches or furrows marked on the surface.

SCUTELLA. Brod. (Scutellum, a little shield.) Fam. Phyllidiana, Lam.—Descr. Shaped like Ancylus, pearly within; apex posteriorly inclined, central, involute; muscular impressions two, oblong, ovate, lateral; aperture large, ovate.—Obs. This genus is intermediate between Ancylus and Patella; while in the aspect of the beak, the observer is reminded of Navicella.

SCUTIBRANCHIATA. Bl. (Scutum, a shield; branchiæ, gills.) The third order of Paracephalophora Hermaphrodita, Bl. containing animals with patelliform, but not symmetrical shells, and divided into the families Otidea and Calyptracea.

SCUTUM. Montf. (A shield.) Parmophorus elongatus, Lam.

SECURIFORM. (Securis, an axe; forma, shape.) Hatchet-shaped. Ex. Pedum, fig. 179.

SEDENTARY ANNELIDES. Lam. The third order of the class Annelides, Lam. distinguished from the two other orders by the circumstance of the animal being enveloped by a shelly tube which it never entirely leaves. The order is divided into the families Dorsalia, Maldania, Serpulacea, and Amphitrites. Fig. 1 to 13.

SEA DATE. The common name for Pholas Dactylus in the market, given to it on account of its cylindrical shape. Fig. 35.

SEGMENTINA. Flem. Nautilus Lacustris, Montagu. Test. Brit. Planorbis nitidus, Drap. tab. 2. Fig. 17 to 19.

SEMICORDATE. Half heart-shaped.

SEMIDISCOIDAL. Forming the half of a circular disc.

SEMILUNAR. Half moon-shaped.

SENECTUS. Humph. A genus of "Senectinæ," thus described by Swainson: "Imperforate; the base produced into a broad flat lobe, spire rather elevated and pointed; the whorls convex; aperture perfectly round; not more oblique than Helix; inner lip entirely wanting, imperialis. Mart. 180. f. 1790. marmoratus. l. M. 448. f. 1." Sw. p. 348.

SEMIPHYLLIDIANA. Lam. The second family of the order Gasteropoda, Lam. the genera of which are distinguished as follows:—