TREMATODES FROM FISHES — ^LINTON 145 



25, 1910, contains coils of the uterus of a distome. The specimen in 

 balsam measures: Length, 3.57 mm.; maximum breadth, about 1 

 mm. ; ova, 0.024 by 0.012 mm. Portions of the uterus are filled with 

 ova, while other portions contain yellow, granular material, presum- 

 ably yolk granules. In some places this material is associated with 

 ova. The size of this fragment suggests a distome of the dimensions 

 of Dinurus pinguis, but the ova are distinctly larger than they are 

 in that species. (U.S.N.M. No. 8378.) 



Family ACCACOELIIDAE Odhner, 1928 



Distomes from the pelagic sunfish, Mola mola, are here considered. 



These are medium to large distomes with elongated and strongly 

 muscular bodies, in most cases smooth; neck short and often more 

 or less reflected dorsally ; ventral sucker larger than oral, often pedi- 

 celled, thus causing the anterior end of the worm to appear to be 

 forked. Pharynx much smaller than oral sucker, usually long-pyri- 

 form; esophagus long, intestinal rami elongate with anterior diver- 

 ticula, giving to the intestine the characteristic H -shape. Excretory 

 vessel Y-form with short stem and short branches; genital pore ven- 

 tral, median, behind oral sucker; copulatory organ muscular; ejacu- 

 latory duct surrounded by prostatic cells; seminal vesicle tubular, 

 convoluted, usually entirely in front of ventral sucker, or dorsal to 

 it. Testes behind ventral sucker, close together, one following the 

 other. Ovary behind testes, median; shell gland at anterior edge of 

 ovary; no seminal receptacle, the sperm being stored in the early 

 folds of the uterus; vitellaria lateral variously distributed in the 

 different species ; uterus voluminous, mainly behind the ovary ; metra- 

 term with muscular walls, ventral to seminal vesicle and prostate; 

 ova numerous, small. The relative positions of structures, especially 

 at the anterior end, are subject to considerable alteration with vary- 

 ing contraction conditions. 



Tlie classification adopted by Odhner ^^ has been followed : 



Genus ACCACOELIUM Monticelli, 1893 



ACCACOELIUM CONTORTUM (Rudolphi) 



Dlstomum contortum (Rudolphi), Linton, Proc. U. S. Nat. Mus., vol. 20, pp. 

 528-530, pi. 48, figs. 3-7, 1898; Bull. U. S. Fish Comm. for 1899, p. 466, 

 1901. — SuMNEK, OsBURN, and Cole, Bull. U. S. Bur. Fisheries, vol. 31, pt. 

 2, p. 582, 1911. 



Accacoelium contortum (Rudolphi), Odhner, Zool. Anz., vol. 77, p. 172, 1928. 



Anterior part of body covered with blunt, papillalike spines; pre- 

 pharynx protrudes into oral sucker, forming a conical papilla ; geni- 



^* Rhynchopharynx paradoxa n. g., n. sp. nebst Revision der Accacoeliden von Ortho- 

 goriscus mola. Zool. Anz., vol. 66, pp. 167-175, 1928. 



155599—40 10 



