THE TREMATODA 



The adults live in Vertebrata, and nearly always in the enteron or its 

 outgrowths ; the intermediate host is usually a mollusc. 



FAMILY 1. AMPHISTOMIDAE. Body more or less cylindrical ; oral 



FIG. X. Some Malacocotyleans. 



Letters common to all the figures, except Fig. 8. o, mouth and oral sucker ; 6, genital 

 pore ; c, posterior ventral sucker. 



1. Amphistomum conicum, Zed., from the paunch of the cow ; ventral view (after Laurer). 

 The genital pore is at the apex of a small papilla surrounded by a shallow groove (cf. Fig. A\ 



2. Homoiogaster paloniae, Poir., from the caecum of I'alonia (Bos) fnmtalis ; ventral view 

 (after Poirier). p, the adhesive papillae covering the ventral surface. 



8. Gastrothylnx cobboldii, Poir., from the stomach of Palonia ; lateral view (after Poirier). 

 The furrow surrounding the genital papilla has become deepened to form a sac (cf. Fig. L), the 

 entrance to which is labelled d. Figs. A and 1: are immediately below 2 and 4 respectively. 



4. Ogmogaster plicata, Crepl., from the caecum of Kalaennptera sp. ; ventral surface (after 

 Jagerskiold). r, the longitudinal ridges constituting a secondary adhesive organ. 



5. Notocotyle sc.riulis, Dies., from the colon of Anas penel&pe; dorsal surface (after Diesing). 

 t, the dorsal suckers in three rows. 



6. Didi/moxoon thynni, Tschbg. ( = Monostomum bipartitum, Wedl.), from a cyst on tho 

 gills of Thynnus vtdgaris (after Wagener). The two individuals are closely wrapped round one 

 another, their "heads" projecting freely. 



7. Anterior sucker of GMfNWMMM jimbriatum, v. Sieb., from the stomacli of the pike 

 (after Wagener). etf, the tentacle-like processes from its margin. 



8. Gasterostomum armatum, Mol., from the intestine of Coitus Scorpio ; ventral view (partly 

 after Molin, partly after Levinsen). 6, genital pore ; e, anterior sucker ; /, vitellarium ; g, 

 simple sac-like intestine ; h, the left vitelline duct, which unites with its fellow, and opens 

 by a median duct into the germ duct ; i, uterus ; j, germarium ; fc, mouth, which has a position 

 unique amongst the Trematoda, nearly in the middle of the ventral surface ; I, the right testis ; 

 m, seminal vesicle ; n, cirrus sac ; o, cirrus or penis ; v, excretory pore. 



9. The smaller of the two individuals of Didymozoon, probably the male. (After Wagener.) 



10. Monostomum mntabile, Zed., from the sub-orbital sinus and body cavity of various 

 aquatic birds. (After P. J. van Beneden.) it, excretory pore. 



11. Opinthotrema cochleare, Lkt., from the tympanic cavity and Eustachian tube of Ilalicore; 

 ventral view (modified from Fischer). The genital pore (b) is posteriorly placed. 



