3. P. felina, linear-oblong, minutely tricuspidate in front, of a uniform dark brown, paler underneath. Length 8""; breadth 1"". Planaria felina, Dalyell on Planariæ, 42. f. 8 (1814). Planaria cornuta, Johnson in Phil. Trans. 1822, 437. pl. 49. f. 1, 7, 9, 10, 13 & 16; and lib. ibid. 1825, 249 & 251. pl. 16. f. 1, 2, 4-8. Planaria viganensis, Dugés in Ann. des Sc. nat. xxi. 84, 91. pl. 2. f. 23 (1830). Polycelis nigra, var. viganensis, Dies. Syst. Helm. i. 192. Hab. Stagnant waters in which aquatic vegetables abound: rarely in springs. Obs. Longer in proportion to its length than the preceding, and more decidedly auricled in front: in shape it is rather elliptical than oblong, tapering backwards from about the middle; whereas in nigra and brunnea, the sides, a little sinuated behind the head, continue parallel until near the tail, which is narrowed and obtuse. 5. PLANARIA. Planaria, Müll. Zool. Dan. Prod. xxviii. (1776). Blainville in Dict. des Sc. nat. lvii. 578. Oersted, Entw. Plattw. 52. Diesing, Syst. Helm. i. 202. Char. Body narrow-oblong, flattish, the front truncate, more or less auricled on each side, the tail rounded: eyes two, placed on the anterior part of the back, parallel. *Freshwater. 1. P. lactea, white, roseate or brownish, with a milk-white mesial spot. Length 6-9""; breadth 14-2"". Fasciola lactea, Müll. Verm. i. ii. 61. Planaria lactea, Müll. Zool. Dan. Prod. no. 2687; Zool. Dan. iii. 47. tab. 109. f. 1, 2. Turt. Gmel. iv. 64. Stew. Elem. ii. 355. Bosc, Vers, i. 303. Rees' Cyclop. xxvii. verb. Planaria. Blainv. Dict. des Sc. nat. lvii. 578. Lam. An. s. Vert. iii. 179; 2de edit. iii. 607. Johnson in Phil. Trans. 1822, 438. pl. 49. f. 4, 5, 11, 15 & 17. Baer in Nov. Act. Curios. xiii. 705. tab. 33. f. 1, 2, 8-11 (1826). Dugés in Ann. des Sc. nat. xv. 144. pl. 4. f. 12; Edin. Journ. Nat. and Geogr. Sc. iii. 242 & 243. W. Thompson in Ann. & Mag. Nat. Hist. xviii. 388. Dalyell, Pow. Creat. ii. 107. pl. 16. f. 5–9, and pl. 15. f. 4-6. Dies. Syst. Helm. i. 203. Hirudo alba, Kirby in Linn. Trans. ii. 316. Planaria alba, Turt. Brit. Faun. 129. Dendrocœlum lacteum, Oersted, Entw. Plattw. 52. Hab. In cold springs and lakes, not common: gregarious. Obs. The front is truncate and even, scarcely auricled. There are occasionally four eyes, when the anterior pair is very minute. Readily distinguished by its white colour. Dark individuals owe their taint to the substance they have been recently feeding upon; and resume their natural fairness after a short abstinence. 2. P. torva, cinereous or black on the dorsal, greyish on the ventral surface; the front obtuse, rounded on the angles and projecting in the centre; eyes each with a white halo. Length 6""; breadth 1-2"". Fasciola torva, Müll. Verm. i. ii. 62 (1773). Planaria torva, Müll. Zool. Dan. Prod. no. 2688; Zool. Dan. iii. 48. Planaria fusca, Rees' Cyclop. xxvii. art. Planaria. Stew. Elem. ii. 355. Planaria subtentaculata, Dugés in Ann. des Sc. Nat. xv. 144. pl. 4. Hub. In lakes and runlets, more especially in those descending from elevated grounds. I believe rare. Obs. I can find no proof that Pl. fusca of Pallas or of Dugés (for it is not certain that they are synonymous) is indigenous. Those authors who have introduced it into their lists have not critically examined the genus. The same remark may be made of Planaria stagnalis, Müll. Templeton has introduced it into his Irish list (Loud. Mag. N. Hist. ix. 239); but he gives no description, nor mentions any locality. 3. P. arethusa, truncate and auriculate in front, leaden or slate-grey, paler underneath; a black eye on a white spot on each side of the medial line in front. Length 6""; breadth 1"". Planaria arethusa, Dalyell, Planar. 85. f. 11-14. W. Thompson in Ann. & Mag. Nat. Hist. ser. 2. vii. 502. Dalyell, Pow. Creat. ii. 111. pl. 16. f. 10-19. Planaria torva, Johnson in Phil. Trans. 1822, pl. 49. f. 2, 8, 14, and ibid. 1825, 251. Hab. In pure springs and rivulets: common. (a) Dods'-well, Berwick, Dr. Johnston. 4. P. edinensis, linear-oblong, rather narrowish forwards, pale carnation; head obtuse, rose-colour; eyes nearly marginal in the rose-coloured part. Length 3""; breadth 1"". Planaria edinensis, Dalyell, Planar. 133. f. 18 (1814). Dies. Syst. Dalyellia edinensis, Johnston in Ann. & Mag. Nat. Hist. xvi. 438. Hab. In pure springs: rare. ** Marine. 5. P. ulvæ, of an olive mottled colour, with a pale abbreviated mesial line; front truncate, distinctly auricled; the tail truncate or more commonly emarginate. Length 5""; breadth 11"". Planaria ulvæ, Oersted, Entw. Plattw. 53. f. 5. Dies. Syst. Helm. i. 205. Hab. At the roots of the Laminaria between tide-marks. (a) Berwick Bay, Dr. Johnston. 6. P. affinis, linear-oblong, rounded and slightly enlarged at the front, of a wood-brown colour, with an oblong white line on the posterior half; eyes a little behind the front, each in the centre of a white spot on the sides of the mesial line. Length 3""; breadth 3"". Planaria affinis, Oersted, Entw. Plattw. 54 (1844). Dies. Syst. Helm. i. 206. Planaria hebes, Dalyell, Pow. Creat. ii. 107. pl. 16. f. 3, 4. Hab. Amongst algae between tide-marks. 7. P.? alba, linear-oblong, obtuse at both extremities, the anterior narrowest; pure white; eyes black, placed backwards and wide apart. Length 3""; breadth "". Planaria alba, Dalyell, Pow. Creat. ii. pl. 16. f. 21, 22. Hab. Shores of Scotland, Dalyell. Obs. Dalyell remarks that the intestinal canal is not pinnate. 8. P. variegata, linear-oblong, a little bulged in the middle, truncate in front, acuminated behind, fasciated across the back with black and yellow belts; eyes two, black, considerably apart. Length 11"; breadth "". Planaria variegata, Dalyell, Pow. Creat. ii. 115. pl. 16. f. 20. Hab. Coast of Scotland, very rare, Dalyell. Obs. This may prove to be a species of the molluscous genus Limapontia. "This is a beautiful animal, plump and heavy, the belly flattened. In crawling up the side of a vessel, it is liable to drop to the bottom, but its descent seems to be retarded by an invisible thread."-Dalyell. The following are doubtful members of this family : Planaria gracilis, body rather linear, acute behind, flattened, white; eyes two, black, placed forwards. Length "". Planaria gracilis, Dalyell, Pow. Creat. ii. 116. pl. 16. f. 23. Hab. Lochend, Dalyell. Obs. The mouth is apparently below, under the eyes. The motion is swift; and the creature can swim in the water. Planaria falcata, body flattened, thick and fleshy, linear-elongate, rounded and equal at both ends; eyes two, lateral, red. Length 1-2 Planaria falcata, Dalyell, Pow. Creat. ii. 117. pl. 16. f. 26–29. Hab. Lochend in autumn, Dalyell. Obs. "Two red crescents apart on the extremity of the head, in a circular position, but under considerable magnifiers, appearing red streaks, sometimes consisting of one or two confluent pair indistinctly The mouth seems in front; and the intestine a longitudinal series of cavities, with some enlargement in their course. Crawls on the belly, or swims swiftly through the water."-Dalyell. seen. Fam. III. DALYELLIDE. RHABDOCELA, Oersted, Entw. Plattw. 59. Ray Soc. Zool. Rep. 1847, 518. Schultze, Naturg. Turbell. 5. GYRATRICINEA, Diesing, Syst. Helm. i. 218. Obs. An artificial group, but associated by a general resemblance in form, and by similarity in habits. They are small animals, of a parenchymatous consistency, in which it is often difficult to trace any distinctly defined viscera, or their openings on the surface. The body is acephalous, and more or less contractile, with an entire margin. They are either marine or lacustrine; and the latter, in general, lay their eggs enclosed in a cocoon or capsule. Of the mode in which the marine genera are propagated, nothing appears to be known. 6. DALYELLIA. Dalyellia, Fleming, Phil. Zool. ii. 605 (1822). Char. Body somewhat compressed vertically, elliptical; the mouth terminal; eyes two, parallel, posterior to the mouth and dorsal. Ova capsulated. Lacustrine. 1. D. helluo, narrowed at both ends, most so posteriorly, of a uniform grass-green colour with a transparent margin; eyes black. Length 1-11"". Fasciola helluo, Müll. Verm. i. ii. 64. Planaria helluo, Müll. Zool. Dan. Prod. no. 2692; Zool. Dan. iii. 39. Hirudo viridis, Shaw in Linn. Trans. i. 94. pl. 7. Johnson on Medic. Planaria viridis, Turt. Brit. Faun. 129. Stew. Elem. ii. 355. Mag. Nat. Hist. xvi. 438. Distigma? helluo, Dies. Syst. Helm. i. 188. Hab. Stagnant water. Obs. The cocoon is brown and oval, apparent near the posterior end: it contains from four to twelve ova. 2. D. exigua, ovate-oblong, broadest behind, reddish; eyes black. Length "". Planaria exigua, Dalyell, Pow. Creat. ii. 116. pl. 15. f. 13, 14. Hab. Ponds. Obs. When in motion, the form is that of a double cone. 7. DEROSTOMA. Derostoma (—), Dugés in Ann. des Sc. nat. xxi. 76 (1830). = Oerst. Char. Body linear-oblong, rounded at both ends, with two eyes or none: mouth pitcher-shaped, concealed, opening by a longitudinal fissure on the venter. 1. D. unipunctatum, plump, narrowed towards the anterior extremity, and obtuse behind, dingy yellow; eyes two, yellow. Length 3""; breadth 1"". Derostoma unipunctatum, Oersted, Entw. Plattw. 66. tab. 2. f. 25. Planaria fodina-the Quarry Planaria, Dalyell, Pow. Creat. ii. 110. Hab. Ponds with a muddy bottom. Obs. The specific name is derived from the spot formed by the brown or yellow cocoon in a position behind the mouth. 2. D.? vorax, body round, obtuse in front, tapered backwards to a point, greenish; eyes none. Length 14""; breadth "". Planaria vorax, Dalyell, Pow. Creat. ii. 119. pl. 16. f. 33, 34. Hab. Freshwater marshes. Obs. When gorged with food resembles an inflated vesicle, tapered downwards. The food is seen to fill a capacious ovoidal stomach. There are, in the pregnant mother, from one to five brown cocoons lodged towards the posterior part. 8. MESOSTOMA *. Mesostoma, Oersted, Entw. Plattw. 67. Mesostomum, Diesing, Syst. Helm. i. 219. Schultze, Naturg. der *Dugés is the author of the name, and the genus was probably founded in 1830, not earlier than 1828. Agassiz has not mentioned it, but he has Myozostoma of much later creation. |