7. STYLARIA. Stylaria, Lam. An. s. Vert. iii. 223 (1816). Ehrenberg in Lam. An. s. Vert. 2de édit. iii. 612. Oersted in lib. cit. 133. Char. Body linear, round, flattish in front: four first segments divided by a stricture from the body, and the first or head prolonged into a filiform appendage: eyes 2: superior bristles capillary, protruded; the inferior forked spinets. 1. S. lacustris. Mille-pied à dard, Trembley, Polyp. 144. pl. 6. f. 1. A very small and slender Worm, Baker, Employm. Microsc. 317. pl. 12. f. 24. Nereis lacustris, Linn. Syst. 1085. Rössel, Insect. iii. 477. tab. 78. Stylaria paludosa, Lam. An. s. Vert. iii. 224; 2de édit. iii. 675. Stylaria lacustris, Templeton in Loud. Mag. Nat. Hist. ix. 235. Hab. About the roots of aquatic plants. Obs. Length 6-7""; segments 60-70; the middle ones nearly twice as broad as long, regularly decreasing backwards; superior bristles twice as long as the breadth of the body, the inferior uncinate, with an incisure about the middle. 8. SERPENTINA. Serpentina, Oersted, lib. cit. 134 (1843). Char. Body linear, round, not flattened in front: the head anguiform, with a produced lower lip: eyes 2: superior bristles subulate, the inferior forked or uncinate. 1. S. quadristriata. Nais serpentina, Müll. Wurm. 84. tab. 4. f. 1-4; Verm. i. ii. 20. Turt. Hab. In ditches amongst duck-weed. Obs. The spinets (inferior bristles) have a globular swelling a little below the middle. The superior are geminate, subulate, and strong. Length of the body 16-18", composed of eighty to ninety segments: head marked with four dark transverse fasciæ. 9. NAIS. Nais, Lam. An. s. Vert. iii. 222. Leach in Supp. Encyclop. Brit. i. 451. Ehrenberg in Lam. An. s. Vert. 2de édit. iii. 612. Oersted in lib. cit. 135. Char. Body linear, subcylindrical, acuminate in front, truncate behind head (= the three or four first segments) continuous with the body, not produced: eyes 2 or none: superior bristles capillary (sometimes uncinate), the inferior forked. 1. N. scotica, bristles shorter than the diameter of the body, fasciculate. Length 1". Nais lacustris, Dalyell, Pow. Creat. ii. 130. pl. 17. f. 1–5. Hab. At the roots of subaquatic plants. Desc. "Length an inch; body round; extremities obtuse; the anterior smooth and cylindrical, the portion behind it provided with a double row of thin tufts of prickles, some of them composed of several bristles. The extremities contain the mouth, and the termination of the excretory canal." "The mouth seems a dilatable cylinder without a proboscis."-Dalyell. 2. N. filiformis. Nais filiformis, Williams in Rep. Brit. Assoc. 1851, 182 & 263. Hab. Freshwater pools, abundant, Dr. Williams. Obs. I cannot say whether this is a new species, or a Müllerian one under a new name. There is no description. 10. CHETOGASTER. Chaëtogaster, Baer in Nov. Act. Curios. xiii. (1826). Oersted in Char. Body cylindrical, truncate in front: eyes none: mouth terminal, barbed underneath on the first segment: bristles all spinets forked at the apex. 1. Ch. vermicularis. Nais vermicularis, Müll. Verm. i. ii. 20. Turt. Gmel. iv. 91; Brit. Nais diaphana, Gruithuisen in Zool. Journ. v. 380. Chatogaster Limnei, Bäer in Nov. Act. Curios. xiii. tab. xxix. f. 23. Hab. Amongst Lemnæ in ditches. Obs. Body cylindrical, hyaline, 10-12"" in length, of eighteen to twenty obsoletely defined segments, the two first twice as long as broad, the others not so long as their diameter: mouth wide: bristles twelve underneath the first segment, in the other segments there are eight of lesser size. I have implicitly followed Oersted in his arrangement and definition of the Naides, for I have not been fortunate enough to meet with a single species. 73 V. GYMNOCOPA. GYMNOCOPA, Grube, Fam. Annel. 27. Char. Body exannular, asetigerous, gelatinous, glauciform, with a series of compressed fins on each side: head distinct, tentaculated, with "a kind of bristles" in the setaceous tentacula. Sexes separate. Vascular system obsolete or very slightly developed. Swimmers. Marine. Fam. I. TOMOPTERIDE. TOMOPTERIDEA, Grube, Fam. Annel. 95. Char. Body elongated, elliptical, with compressed fins, little developed or obsolete towards the posterior extremity: segments not numerous, and not divided by sutures. Head continuous with the post-occipital segment, furnished with frontal tentacula, and with very long lateral tentacular filaments, both containing a setiform portion: eyes 2: mouth ventral, edentulous. Fins or feet two-lobed, without bristles. 1. TOMOPTERIS, Eschscholtz, 1825. Tomopteris, Grube, Fam. Nat. 96. Johnstonella, Gosse's Ramb. Devon. Coast, 356; see also Gray, Ann. & Mag. Nat. Hist. ser. 2. xii. 150 & 199. Char. The only genus. 1. T. onisciformis. Tomopteris onisciformis, Grube, Fam. Annel. 96. Johnstonella Catharina, Gosse, Ramb. Devon. Coast, 356. pl. 25. Hab. The sea-coast of S. Devon, P. H. Gosse. Desc. "Body inch long, inch in greatest diameter, flat, thin, as transparent and colourless as glass. Head dilated on each side into two lobes, which are flat, pointed, and leaf-like, extending laterally to a considerable distance. Along the posterior pair are soldered a pair of excessively long, slender antennæ, tapering to a fine point; they appear simple unjointed filaments, directed divergently backwards to a greater length than the body, and incapable of changing in direction. The basal moiety of their length is invested with a loose skin, which corrugates into folds. Eyes two, black, small, on the summit of the head, between the posterior lobes: a line of minute black specks runs down the middle of the neck behind the eyes. Body narrow at each extremity, widening in the middle, furnished on each side with sixteen fin-like narrow lobes, each of which bears at its extremity two oval branchial? leaves set on obliquely. The ultimate pairs diminish gradually, and are succeeded by a few pairs of rudimentary processes on each side of a slender tail. Viscera:-a simple, clear, rather wide canal running through the whole length, ordinarily parallel-sided, but sometimes constricted so as to form a succession of spindle-shaped divisions, which pass from the head to the tail in rather slow pulsations, like the dorsal vessel of a caterpillar. A thick œsophageal proboscis was once protruded from the mouth, of an obconic form, with a large somewhat four-sided orifice obliquely terminal. No other internal structure was visible, notwithstanding the perfect transparency of the animal.” "Three specimens of the Johnstonella have come into my possession, all of which were dipped from the surface of the sea off the harbour of Ilfracombe, about the end of August. In a glass jar their motions were excessively vivacious; they swam with great swiftness by the rapid vibration of the lateral fins; so incessantly, that it was with the utmost difficulty I could examine them with the microscope. They darted through the water in all directions, across and around the jar; and when they rested, their translucency rendered them almost invisible. They soon died in captivity; I think I did not keep one of them longer than the second day.”—P. H. Gosse. "The animal described by Mr. Gosse under the name of Johnstonella Catharina appears to belong to the same genus as the animal described by Eschscholtz in the Isis' (1825), p. 736. t. 5. f. 5, under the name of Tomopteris onisciformis from the South Seas; and by MM. Quoy and Gaimard in the Voyage of the Astrolabe,' ii. p. 284. t. 21. f. 21, 24, under the name of Briarca Scolopendra from the coast of Spain. Hermannsen has proposed to change the latter name to Briaræa: Harry Goodsir calls it Briareus: and Mr. R. Ball writes it Bryarea. Eschscholtz and Quoy and Gaimard regard it as a mollusk; the first referring it to the order Heteropoda, and the latter to the Nudibranchiata. "Mr. Harry Goodsir, who found the animal abundant in the North Sea (Ann. and Mag. Nat. Hist. 1845, xvi. 163)," observing the presence of "cilia fringing the bifurcated posteriors of the lateral extremity of its body," decided that it could not be a mollusk. "Menke (Zeitschr. für Malac. 1844, p. 21) proposes to remove the genus to the Annelides; more recent authors have considered it as a Crustacean. "Mr. Gosse at first sight thought it might be a Brachiopod Crustacean, but thinks it has more affinity to the Annelides (p. 348), and refers it to that class in the Systematic Index. According to Eschscholtz and Quoy and Gaimard, the South Sea specimens are very much smaller than those found in the Mediter |