316 PLATTHELMINTHES. 



elongated and flattened body, which is provided with a foot-like ventral surface. 

 Geoplanalapidicola Stimps., Rhynchodesmus terrestrial Gm. {Fasdola tcrrr.xtris, 

 0. Fr. Miiller), Europe. Geodeftinuis biliiieatus, Metschn.. with thread cells in 

 the integument, found in potter's earth. 



2. Dig'Onopora. Dendroccela with double sexual opening. Almost 

 all are marine. The proboscis is often folded and lies within a 

 special pouch. When protruded, it spreads out like a lobe. 



Fam. Stylochidae. The body is flat and rather thick, and is provided with 

 two short tentacles on the head. There are usually numerous eyes on the 

 tentacles or on the head. The genital openings are posterior. ftfylorJt-tts macu- 

 latiix Quatr. 



Fam. Leptoplanidse. Body flat and broad, usually very delicate. Cephalic 

 region not distinct, without tentacles. The eyes are more or less numerous. 

 The mouth is usually placed in front of the middle of the body. The genital 

 openings lie behind it. Leptoplana troni'llarix O, Fr. Mull., Mediterranean. 



Fam. Euryleptidae. Body broad, and cither smooth or furnished with 

 papillae. There are two tentacle-like lobes on the anterior region of the head. 

 The mouth is placed in front of the middle of the body. Numerous eyes are 

 disposed near the anterior margin. Marine. Thi/x/ni/i-nnn Difxinyii, Gr. 

 Mediterranean. Eurylepta auriculntu 0. Fr. Miiller. North Sea. 



Order 2. TREMATODA.* 



Parasitic Platyhelminthes with unsegmented, usually leaf-shaped, 

 rarely cylindrical body. They possess a mouth and ventrally placed 

 organ for attachment : the intestine is forked and without an anus. 



The Trematodes are with great probability to be derived from 

 the Turbellaria, with which group, both in form and organization, 

 they show a close relationship. In connection with their parasitic 

 mode of life they develop special organs for adhering, such as 

 suckers and hooks. Cilia are present only in larval life. 



The mouth is invariably placed at the anterior end of the body, 

 usually in the middle of a small sucker (tig. 253). It leads into 

 a muscular pharynx with a more or less elongated oesophagus, which 

 is prolonged into a forked intestine ending blindly. 



Moseley, ' Notes on the Structure of Several Forms of Land Planarians." etc. 

 Journal of Jfio 4 . Kelt-net', vol. xvii. 



* A. v. Nordmann, ' Mikrographischc Beitriige zur Kenutniss der wirbellosen 

 Thiere." Berlin. 1832. G. G. Cams. " Beobachtung iiber Leucochloridium 

 paradoxum, etc.," Nov. Aft., vol. xvii., 1835. Wagener. " Ueber Gyrodactylus 

 elegans," Muller'x Arcltlv.. 18(iO. Van Beneden, " Memoire sur les vers intes- 

 tinaux." Paris, 18(11. E. Zeller, Untersuchungen iiber die Entwickelung und 

 den Bau von Polystoma integerrimum. Zfifxrhr. f. n-/xx. ZouL, vol. xxii., 1872. 

 E. Zeller, " Untersuchungen iiber die Entwickelung von Diplozoum paradox- 

 urn.'' Ibid., vol. xxiii., 1878. E. Zeller. ' Ueber Leucochloridium paradoxum 

 und die weitere Entwickelung seiner Distomumbrut." Ibid.. Tom XXIV. 

 E, Zeller, Weitcrcr Beitragzur Kenntniss der Polystomeen," Ibid., xxvii., 1876. 

 Compare also the works of G. Wagener and De Filippi. 



