TREMATODES FROM FISHES LINTON 41 



ends of the excretory vessels were mistaken for diverticula of the intestine) ; 

 Bull. U. S. Bur. Fish., vol. 31, pt. 2, p. 584, 1911. 

 Lintonium viiex (Linton), Stuxkabd and Nigeeixi, Biol. Bull., vol. 58, pp. 33&- 

 343, 1 fig., 1930. 



On account of the close resemblance of this distome to Sienngopho- 

 711S cluthensis NicoU, later referred by Odhner to a new genus, I was 

 inclined to refer D. vihex to that genus. Since Prof. Stunkard, 

 however, has evidenth' gone over the ground with great care, I 

 shall accept his conclusions. 



As supplementary to Prof. Stunkard's contribution a few observa- 

 tions on this interesting distome, together with a record of collections 

 made by Vinal N. Edwards and myself in the Woods Hole region 

 since 1901, are given. 



Body smooth, longer than broad, flattened in life, or more or less 

 fusiform, plump in preserved material, greatest diameter at about 

 middle of postacetabular region, tapering to anterior end, posterior 

 end bluntly pointed; ventral sucker much larger than oral; no pre- 

 pharynx; esophagus short or lacking; pharynx much smaller than 

 oral sucker; intestinal rami simple, extending nearly to posterior 

 end. The genital pore is on the median line, behind the pharynx; 

 cirrus spinose; cirrus pouch oval-elliptical, enclosing the seminal 

 vesicle and prostate, and lying in front of the ventral sucker. Testes 

 oval, opposite, usually a little in front of the middle of the postace- 

 tabular region. The testes are, with few exceptions, longer than 

 broad. Out of 20 spechnens mounted in balsam there is only one in 

 which the testes are broader than long, and in it there is some indi- 

 cation that the testes are distorted; an average of the testes of 20 

 specimens in balsam gave a length of 0.36 mm. and a breadth of 0.22 

 mm. The ovary is trilobed and usually lies about on the median 

 line behind the ventral sucker, its posterior half between the anterior 

 thirds of the testes. In some cases it is near the posterior border 

 of the ventral sucker and in front of the testes. The shell gland, in 

 whole mounts, appears to lie on the left side of the ovary and to ex- 

 tend anteriorly a little in front of the ovary, where it is joined by the 

 yolk ducts. On account of the thickness of these distomes the rela- 

 tive positions of these organs are not easily seen. An examination of 

 sections shows that the ovary is dorsally placed; in strongly con- 

 tracted specimens it can be seen to be dorsal to the posterior border 

 of the ventral sucker. The shell gland is ventral to the ovary, and 

 the testes are also vent rally placed. Laurer's canal was traced in a 

 somewhat sinuous course in a series of cross sections from the dorsal 

 surface to the shell gland. It was also noted in a series of sagittal 

 sections (pi. 20, fig. 270). The early folds of the uterus are filled 

 with sj^erm in which ova are intermingled. The voluminous folds 



