316 PLATYIIELMINTILES. 



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

 <;< a/,], i /in l/i/iiifii-iifii Stimps.. Ilhy/i-hiiiJi-siitH-g terrestrls Gm. (FascioltKterrestra, 

 0. Fr. Miiller), Europe. Gcutle-tinns liliiir.itus, Metschn., with thread cells in 

 the integument, found in potter's earth. 



2. Digonopora. Dendroc<da 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. Mylorhus wnci/- 

 lufiix Quatr. 



Fam. Leptoplanidae. 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. Lcptoplann trenu-llaris 0, Fr. Miill.. Mediterranean. 



Fain. Euryleptidae. Body broad, and either smooth or furnished with 

 papilla?. There are two tentacle-like lobe? 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. T/tyx/tHnzoon Dicsingli Gr. 

 Mediterranean. Eurylejita avricnlata 0. Fr. Miiller, North Sea. 



Order 2. TREMATODA.* 



Parasitic Platyhelminthes ivith unsetj 'mented, 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 Treniatodes 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 Mlrr. /s'c/V /tcr. vol. xvii. 



* A. v. Nordmnim. " Mikroirraphische Beitriige zur Kenntniss der wirbclin.-. n 

 Thiere," Berlin, 1832. G. G. Cants, " Beolmditung iii><T Leucochloridium 

 paradoxum, etc.." l\'r. Act., vol. xvii.. is:',n. AVngt-in'r. " t'rlH-r Gyrodactylus 

 elccans," Mitllrr'x An-liu:. isiiit. Van Jleneden. " Mni'ohv MIT lr> vers intes- 

 tinaux," 1'aris. ]8<'.l. E. Zellcr. " rntcrsucliujigen iibi'i-ilii' Kntwirki'liniu' und 

 den Ban von 1'olysioiua intcjrtrriniuin, /< it*i-/tr. f. iris*. Zm'l., vol. xxii., 1S72. 

 E. Zellcr, " Untersiichuiigeii iiber die Entvvickelung von Diplozoum paradox- 

 urn," Ibid., vol. .\.\iii., 187:5. E. Zdlcr. " Qeber Leucoohloridium iiaiadoxum 

 und die weitere Entwickehni.LT seiner I >i^ioinuml>nii ." JliiL. Tom XXIV. 

 E. Zcller, " Weitercr Beitragzur Kenntnifis dcr Polystomcen," Ibid., xxvii., 1S7G. 

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



