BY PROFESSOR W. A. HAS WELL. 513 



The mouth is situated on the ventral surface considerably 

 behind the middle. It leads into a rounded pharynx, from which 

 the simple intestine leads forwards as far as, or further than, the 

 middle of the length of the body. No contents of any kind were 

 ever observed. Behind the mouth and pharynx are two irregular 

 masses of cells, forming a slightly uns3niimetrical pair; these are 

 apparently rudiments of the gonads. Close to them in the middle 

 is the excretory sac. 



The tail consists of a basal part and two long branches or 

 appendages. The former is somewhat elliptical, with the long 

 axis transverse, the anterior border nearly straight, or at least 

 less convex than the posterior. The branches are attached to the 

 basal part antero-laterally; they are slender, nearly twice the 

 length of the body, and taper slightly at the extremity. 



LITERATURE. 



1. — Baer, K. E. von.^ — " Beitrage zur Kenntniss der niederen Thiere. " Nova 



act. Caes, L. C. Nat. Cur. Vol. xiii. 1827. 

 2. — BiEHRiNGER, J. — " Beltiage zur Anat. u. Entw. der Trematoden." 



Arb. Zool.-zoot. Inst, in Wiirzburg, viii. 1885. 

 3. — Braun, M. — "Vermes" of Bronn's ' Thierreich.' 

 4. — Heckert, G. — " Zur Naturgeschichte des Leucochloridium para- 



doxum." Zool. Anz. x. 1887. 

 5. — Lacaze-Duthiers, H. — " Memoire sur le Bucephale Haime, helminthe 



parasite des huitres et des bucardes." Ann. Sci. nat. 4 ser. 



Tome i. 1854. 

 6. — Leuckart, R. — " Die Menschliche Parasiten," 1863. 

 7. " Zur Entwickelungsgeschichte des Leberegels." Zool. 



Anz. 1881 and 1882. 

 8. " Zur Entwickelungsgeschichte des Lebo'egels." Arch. 



f. Naturg. 48, 1882. 

 9. — Loos, A. — " Ueber Amphistomum subclavatum, Rud., und seine Ent- 



wickelung." Festschrift fiir Leuckart, 1892. 

 10. — Pagenstecher, a. H. — " Untersuchungen liber niedere Seethiere aus 



Cette." Zeitschr. f. wiss. Zool. 12, 1868. 

 11. — Reuss — " Beobachtungen an der Sporocyste und Cercarie des Disto- 



mum duplicatum, Baer." Zool. Anz. 25, 1902. 

 12. — ScHWARZE, W. — "Die postembryonale Entwickelung der Trematoden." 



Zeitschr. f. wiss. Zool. 43, 1886. 



