Genera.—Gonium (O.F. Müller) (Fig. 1, 14); Stephanosphaera (Cohn); Pandorina (Bory de Vine); Eudorina (Ehr.); Volvox (Ehr.) (Fig. 1, 18, 20).
The sexual reproduction of the colonies of the Volvocaceae is one of the most important phenomena presented by the Protozoa. In some families of Flagellata full-grown individuals become amoeboid, fuse, encyst, and then break up into flagellate spores which develop simply to the parental form (Fig. 1, 23 to 26). In the Chlamydomonadidae a single adult individual by division produces small individuals, so-called “microgametes.” These conjugate with one another or with similar microgametes formed by other adults (as in Chlorogonium, Fig. 1, 7); or more rarely in certain genera a microgamete conjugates with an ordinary individual megagamete. The result in either case is a “zygote,” a cell formed by fusion of two which divides in the usual way to produce new individuals. The microgamete in this case is the male element and equivalent to a spermatozoon; the megagamete is the female and equivalent to an egg-cell. The zygote is a “fertilized egg,” or oosperm. In some colony-building forms we find that only certain cells produce by division microgametes; and, regarding the colony as a multicellular individual, we may consider these cells as testis-cells and their microgametes as spermatozoa.
Cystoflagellata(Rhynchoflagellata of E.R. Lankester) and Dinoflagellata are scarcely more than subdivisions of Flagellata; but, following O. Bütschli, we describe them separately; the three groups being united into his Mastigophora.
Further Remarks on the Flagellates.—Besides the work of special Protozoologists, such as F. Cienkowski, O. Bütschli, F. v. Stein, F. Schaudinn, W. Saville Kent, &c., the Flagellates have been a favourite study with botanists, especially algologists: we may cite N. Pringsheim, F. Cohn, W.C. Williamson, W. Zopf, P.A. Dangeard, G. Klebs, G. Senn, F. Schütt; the reason for this is obvious. They present a wide range of structure, from the simple amoeboid genera to the highly differentiated cells of Euglenaceae, and the complex colonies of Proterospongia and Volvox. By some they are regarded as the parent-group of the whole of the Protozoa—a position which may perhaps better be assigned to the Proteomyxa; but they seem undoubtedly ancestral to Dinoflagellates and to Cystoflagellates, as well as to Sporozoa, and presumably to Infusoria. Moreover, the only distinction between the Chlamydomonadidae and the true green Algae or Chlorophyceae is that when the former divide in the resting condition, or are held together by gelatinization of the older cell-walls (Palmella state), they round off and separate, while the latter divide by a “party wall” so as to give rise either to a cylindrical filament when the partitions are parallel and the axis of growth constant (Conferva type), or to a plate of tissue when the directions alternate in a plane. The same holds good for the Chrysomonadaceae and Cryptomonadaceae, so that these little groups are included in all text-books of botany. Again among Fungi, the zoospores of the Zoosporous Phycomycetes (Chytrydiaceae, Peronosporaceae, Saprolegniaceae) have the characters of the Bodonidae. Thus in two directions the Flagellates lead up to undoubted Plants. Probably also the Chlamydomonads have an ancestral relation to the Conjugatae in the widest sense, and the Chrysomonadaceae to the Diatomaceae; both groups of obscure affinity, since even the reproductive bodies have no special organs of locomotion. For these reasons the Volvocaceae, Chloromonadaceae, Chrysomonadaceae and Cryptomonadaceae have been united as Phytoflagellates; and the Euglenaceae might well be added to these. It is easy to understand the relation of the saprophytic and the holophytic Flagellates to true plants. The capacity to absorb nutritive matter in solution (as contrasted with the ingestion of solid matter) renders the encysted condition compatible with active growth, and what in holozoic forms is a true hypnocyst, a state in which all functions are put to sleep, is here only a rest from active locomotion, nutrition being only limited by the supply of nutritive matter from without, and—in the case of holophytic species—by the illumination: this latter condition naturally limits the possible growth in thickness in holophytes with undifferentiated tissues. The same considerations apply indeed to the larger parasitic organisms among Sporozoa, such as Gregarines and Myxosporidia and Dolichosporidia, which are giants among Protozoa.
Literature.—W.S. Kent, Manual of the Infusoria, vol. i. Protozoa (1880-1882); O. Bütschli, Die Flagellaten (in Bronn’s Thierreich, vol. i. Protozoa, 1885); these two works contain full bibliographies of the antecedent authors. See also J. Goroschankin (on Chlamydomonads) in Bull. Soc. Nat. (Moscow, iv. v., 1890-1891); G. Klebs, “Flagellatenstudien” in Zeitsch. Wiss. Zool. lv. (1892); Doflein, Protozoen als Krankheitserreger (1900); Senn, “Flagellaten,” in Engler and Prantl’s Pflanzenfamilien, 1 Teil, Abt. 1a (1900); R. Francé, Der Organismus der Craspedomonaden (1897); Grassi and Sandias, “Trichonymphidae,” in Quart. J. Micr. Sci. xxxix.-xl. (1897); Bezzenberger, “Opa inidae” in Arch. Protist, iii. (1903); Marcus Hartog, “Protozoa,” in Cambridge Nat. Hist. vol. i. (1906).
(M. Ha.)
FLAGEOLET, in music, a kind of flute-à-bec with a new fingering, invented in France at the end of the 16th century, and in vogue in England from the end of the 17th to the beginning of the 19th century. The instrument is described and illustrated by Mersenne,[1] who states that the most famous maker and player in his day was Le Vacher. The flageolet differed from the recorder in that it had four finger-holes in front and two thumb-holes at the back instead of seven finger-holes in front and one thumb-hole at the back. This fingering has survived in the French flageolet still used in the provinces of France in small orchestras and for dance music. The arrangement of the holes was as follows: 1, left thumb-hole at the back near mouthpiece; 2 and 3, finger-holes stopped by the left hand; 4, finger-hole stopped by right hand; 5, thumb-hole at the back; 6, hole near the open end. According to Dr Burney (History of Music) the flageolet was invented by the Sieur Juvigny, who played it in the Ballet comique de la Royne, 1581. Dr Edward Browne,[2] writing to his father from Cologne on the 20th of June 1673, relates, “We have with us here one ... and Mr Hadly upon the flagelet, which instrument he hath so improved as to invent large ones and outgoe in sweetnesse all the basses whatsoever upon any other instrument.” About the same time was published Thomas Greeting’s Pleasant Companion; or New Lessons and Instructions for the Flagelet (London, 1675 or 1682), a rare book of which the British Museum does not possess a copy. The instrument retained its popularity until the beginning of the 19th century, when Bainbridge constructed double and triple flageolets.[3] The three tubes were bored parallel through one piece of wood communicating near the mouthpiece which was common to all three. The lowest notes of the respective tubes were
The word flageolet was undoubtedly derived from the medieval Fr. flajol, the primitive whistle-pipe.