In 1882 Bütschli still further increased the number of known Radiolaria from Barbados both by figures and descriptions (L. N. [40]), and gave in particular a very accurate morphological analysis of 12 new Nassellaria (3 Stephoidea, 3 Spyroidea, and 6 Cyrtoidea; L. N. [40], Taf. xxxii., xxxiii.). The number of the fossil species collected in the Barbados marl is, however, greater than would appear from the above-quoted communications. My respected friend, Dr. R. Teuscher, of Jena, has, at my request, made a large number (about a thousand) of very accurate drawings with the camera lucida of Polycystina from Barbados (see p. [1760]). From these it appears that the variations in the structure of the shells, with respect to number, size, and form of the lattice-pores, of the spines, &c., is much greater than would be supposed from the figures of Ehrenberg and Bury. I have thus come to the conviction that the number of species from Barbados (using the word "species" in the sense understood by those authors) is not less than 400 and probably more than 500. Descriptions of some particularly interesting new species from this series have been included in the systematic account of the Challenger Radiolaria. A complete critical investigation of the Radiolaria of Barbados, and especially an accurate comparison of these Cainozoic species with the Mesozoic forms from the Jura, on the one hand, and with recent types on the other, must be left to the future for its accomplishment (see § [246]).
B. The Cainozoic Polycystine tripoli or marl of the Mediterranean coast, which is probably always of Miocene origin, forms very extensive mountain ranges both in the south of Europe (Sicily, Calabria, Greece) and in the north of Africa (from Oran to Tripoli) (§ [246]). Hitherto, however, only one locality has been thoroughly investigated, namely, Grotte in the province of Girgenti in Sicily (L. N. [35]). In the accurate account which was given of it by Stöhr in 1880, 118 species were described, distributed in 40 genera (L. N. [35]; pp. 72-84); of these 118 species 78 are quite new, 25 are identical with previously known fossils, and 29 identical with living forms. Among them are 73 Spumellaria (28 Sphæroidea, 8 Prunoidea, and 37 Discoidea), but only 40 Nassellaria (1 Stephoidea, 6 Spyroidea, and 33 Cyrtoidea), and 5 Phæodaria (Dictyochida). The other parts of Sicily from which the same upper Miocene tripoli has been investigated (belonging to the Tortona stage) have proved less rich than Grotte. The best known of these places is Caltanisetta, since upon three genera discovered here (Haliomma, Cornutella, Lithocampe) the group Polycystina was founded by Ehrenberg in 1838 (see L. N. [16], p. 3). Afterwards 31 species were described from this locality, of which 23 were again found in Grotte. The richest deposit on the Mediterranean coast, however, appears to be at Oran. A small specimen of the Kieselguhr found there, which was recently sent to me by Professor Steinman, proved to be pure Radiolarian ooze, very similar to that now found in the Central Pacific, and contained many hitherto undescribed species; it is deserving of careful investigation and comparison.
C. Regarding the Tertiary Radiolarian clay of the Nicobar Islands, see § [247] and L. N. [25], pp. 116-120. Its fauna is incompletely known; probably it is of Miocene or Oligocene origin.
D. Cainozoic tripoli, containing larger or smaller quantities of Radiolaria, appears to be rather widely distributed in America. Ehrenberg has described such from South America (polishing-slate from Morro di Mijellones, on the coast between Chili and Bolivia), and from North America (Richmond and Petersburg in Virginia, Piscataway in Maryland). Similar deposits are also found in the Bermuda Islands (L. N. [4], 1855-56; L. N. [6], Taf. 18; L. N. [16], pp. 3-9; L. N. [41], pp. 475-478, and L. N. [25], pp. 2-6).
243. Mesozoic Radiolaria.—From the Mesozoic or Secondary period numerous well-preserved Radiolaria have recently been described. They belong for the most part to the Jurassic formation (see notes A, B, C), whilst the more recent Chalk (see note D) and the older Trias (see note E) have hitherto yielded but few species. All the main divisions of the Jura, both the upper (Malm) and the middle (Dogger), and especially the lower (Lias) appear in certain localities to be very rich in well-preserved shells of fossil Polycystina. Most of these are aggregated together in coprolites and quartzites (jasper, chert, flint, &c., § [248]). The majority are Cyrtoidea, the minority Sphæroidea and Discoidea in almost equal proportions; a few Beloidea (Sphærozoum) and Phæocystina (Dictyocha) are also found among them. The general morphological character of these Jurassic Radiolaria is very different from that of the nearly related Tertiary and living forms. In general, their siliceous shells are firmer and more massive, usually also somewhat larger, but of simpler structure. The manifold delicate appendages (spines, bristles, feet, wings, &c.) which are so richly developed in the living Spumellaria and Nassellaria, and are also well shown in the Tertiary species, are entirely wanting in the majority of the Jurassic Polycystina. The Sphæroidea and Prunoidea are all simple spherical or ellipsoidal lattice-shells (Monosphærida); concentric lattice-shells (Polysphærida) are entirely wanting. The Cyrtoidea are, for the most part, devoid of radial processes or basal feet (Eradiata); triradiate and multiradiate forms, such as are found abundantly in the recent and Tertiary formations, are very rare. The large number of many-jointed forms (Stichocyrtida) and of Cyrtoidea with latticed basal opening is very striking.
A. The most important work on the Jurassic Radiolaria, regarding which but little was known prior to the year 1885, is the valuable and in some respects very interesting Beiträge zur Kenntniss der fossilen Radiolarien aus Gesteinen des Jura, by Dr. Rüst of Freiburg i. B. (1885, Palæontographica, Bd. xxxi. 51 pp. with 12 plates). Unfortunately this important work was issued only when about half of the present Report was printed off, so that it was no longer possible to include the 234 species there described in its systematic part. I have therefore elsewhere given a list of the Jurassic Radiolaria, and at present only make the following remarks:—Of the 234 species described, the larger half (130) belong to the Nassellaria (Cyrtoidea), the smaller half (102) to the Spumellaria (38 Sphæroidea, 14 Prunoidea, and 50 Discoidea). In addition, there are 2 Phæodaria depicted, and several spicules which are probably to be referred to the Beloidea. Among the 130 Cyrtoidea (of which 2 are described as Botryodea), there are 24 Monocyrtida, 14 Dicyrtida, 22 Tricyrtida, and 70 Stichocyrtida. Just as striking as the predominant number of the last is the fact that there are only very few triradiate (9) and multiradiate (4) species found among these 130 Cyrtoidea, as also the large number of species with latticed basal opening; Stephoidea appear to be entirely wanting. The rich material of jasper, chert, flint, and coprolites in which Dr. Rüst found these Radiolaria, is derived for the most part from the Jurassic rocks of Germany (Hanover, South Bavaria), Tyrol, and Switzerland (compare § [248]).
B. Jurassic Radiolaria from Italy, also found in jasper, which are closely related to the forms from Germany and Switzerland described by Dr. Rüst, were made known so long ago as 1880 by Dante Pantanelli in his treatise I Diaspri della Toscana e i loro Fossili (Rome, 1880, 33 pp. 60 figs.). Pantanelli believes, however, that this jasper is for the most part of Eocene origin; but from his description, and especially from the morphological character of the forms which he figures, it appears very probable "that these Tuscan jaspers from Galestro, like those of the Swiss conglomerates, are found in a secondary locality and belong to the Jurassic period" (Rüst, L. N. [51], p. 3). Unfortunately the figures of Pantanelli are so small and incomplete that a reliable determination of the species is hardly possible; for example, the lattice-work is only given in ten of the sixty figures. Among the 32 recorded species 15 are Spumellaria (6 Sphæroidea and 9 Discoidea) and 17 Nassellaria (4 Stephoidea and 13 Cyrtoidea); many of which seem to be identical with the forms more accurately described by Dr. Rüst (compare p. [1762]).
C. From the Lias of the Alps and more particularly "from the lower Liassic beds of the Schafberg near Salzburg," Dr. Emil von Dunikowski in 1882 described 18 species of fossil Radiolaria (L. N. [44], pp. 22-34, Taf. iv.-vi.); most of these are Sphæroidea and Discoidea and appear to have been more or less altered by petrological changes; their spongy structure is probably secondary.
D. Cretaceous Radiolaria have been hitherto described only in very small numbers; quite recently Dr. Rüst has found a larger number chiefly in flints from the English chalk, but they have not yet been published. In 1876 Zittel described 6 very well-preserved species from the upper chalk of North Germany (L. N. [29], pp. 76-96, Taf. ii.); among them were 1 Sphæroidea, 1 Discoidea, 1 Dictyocha, and 3 Cyrtoidea.
E. Triassic Radiolaria have recently been discovered by Dr. Rüst in chert, but have not yet been described.