2 TURBELLARTA. 



II. Order. BDELLOMORPIIA. The posterior extremity of the 

 body with a sucker-hke circular disc or with several discs. 



V. Order. GYMNOCOPA. The body hyaline and furnished with 



a series of compressed fins along each side : head distinct, with 



tentacular processes. 



** Body annular. 



III. Order. BDELLIDEA. The anterior and posterior extremity 

 with a sucker-like circular disc. 



B. PoLYPODOUS : the body with bristles along the sides. = Cheto- 

 podes, De Blainville. = Polypoda, Mac^eay. = Ch8etbelmintha, 

 Diesing. 



IV. Order. SCOLOCES. Body vermiform, without external soft 

 appendages; the segments with simple spiniform or setaceous 

 bristles, either single or fasciculate. 



VI. Order. ANNELIDES. Body vermiform, with soft external 

 appendages, and with various bristles collected into fascicles on a 

 more or less protuberant basis. 



Order I. TURBELLARIA. 



Planaria, Mull. Zool. Dan. Prod, xxviii. (1776). Bosc, Vers, i. 290 



(1827). 

 Planaires, Cuv. Regn. Anim. iii. 266. 



Aporocephala, Blainville in Diet, des Sc. nat. Ivii. 573 (1828). 

 Planarie^, Duges in Ann. des Sc. nat. xv. 140 (1828). 

 Turbellaria, Ehrenberg. See Lam. An. s. Vert. 2de edit. iii. 608. 



Agassiz, Nom. Zool. Verm. 

 Nemertina, Macleay in Murchison's Silurian Syst. ii. 699 (1839), 



and in Ann. Nat. Hist. iv. 385. 

 MoLLUSCA parenchymata, Swainson, Malacology, 35. 

 Planaria, Jones' Anim. Kingd. 89. 

 Planariees, M.'Edwards, Elem. Zool. 2de edit. ii. 230. 

 Vermes, Dalyell, Pow. Great, ii. 53 (1853). 

 Turbellariea, Diesing, Syst. Helm. i. 179. 

 Plattwurmer, Oersted, Entwurf Plattw. 1. (1844). 



Char. Worms individual, locomotive, very rarely tubicolous, mon- 

 oecious or dioecious, with or without eyes, the surface usually coloured 

 and sometimes in elegant patterns, transparent or opake. Body soft, 

 parenchymatous or cavernous, flat or subcylindrical, naked and lubri- 

 cous, covered more or less with vibratile cilia, and sometimes with 



