TREMATODES FROM FISHES — LINTON 139 



that the seminal vesicle extends diagonally between the testes from 

 near the ventral to near the dorsal surface. It may be displaced in 

 individuals which are gorged with ova so as to lie on the left side 

 of the ventral sucker. The testes are nearly opposite each other on 

 either side of the seminal vesicle. Sections show them to be slightly 

 lobed. In younger specimens the testes may lie behind the ventral 

 sucker at a distance equal to twice the diameter of the ventral sucker ; 

 in older specimens they may be crowded by the ova to either side of 

 the ventral sucker. The ovary is relatively large, median, imme- 

 diately behind the testes, extending farther ventrally than the testes. 

 The shell gland is at the ventral edge of the ovary. Behind the 

 ovary is the relatively large seminal receptacle. Wliile the laterally 

 placed vitellaria are tubular, in one series of frontal sections, in addi- 

 tion to the tubular vitellaria there is a vitelline mass on the left side 

 0.56 mm. in length and breadth and 0.65 mm. in dorsoventral diam- 

 eter. In this specimen the ovary and testes are at the posterior border 

 of the ventral sucker. The posterior end of the seminal vesicle is 

 dorsal to the ovary and is crowded by the voluminous uterus to the 

 left side of the ventral sucker. In a specimen with relatively few ova 

 the distance from the ventral sucker to each testis and to the seminal 

 vesicle is 0.77 mm., to the ovary, 0.91 mm., to the seminal receptacle, 

 1.18 mm. In a specimen with very many ova the distance from the 

 ventral sucker to the left testis is 0.14 mm., to the seminal receptacle 

 0.42 mm. ; the ovary, right testis, and seminal vesicle are contiguous 

 to the posterior border of the ventral sucker. Estimates made from 

 series of cross sections: (1) In a series, in which the ova had not 

 become crowded in the postacetabular region, the distance from the 

 ventral sucker to the seminal vesicle was 0.56 mm., and to the first 

 testis 1 mm. (2) In a series in which the postacetabular region was 

 crowded with ova the anterior border of the first testis was 0.05 mm., 

 and the anterior end of the seminal vesicle was 0.18 mm. in front of 

 the posterior edge of the ventral sucker. In a series of sagittal sec- 

 tions the ovary is 0.28 mm. in length and 0.42 mm. in dorsoventral 

 diameter, the seminal vesicle 0.77 ram. in length, the seminal 

 receptacle 0.28 mm. in length and 0.70 mm. in dorsoventral diameter. 



Measurements in balsam: Length, 5.5 mm.; breadth, 1.75 mm.; 

 diameter of oral sucker, 0.28 mm., of pharynx, 0.16 mm., of ventral 

 sucker, 0.54 mm. ; distance between oral and ventral suckers, 0.24 mm. ; 

 ova about 0.017 by 0.011 mm. 



From squeteague: One, collected July 15, 1905, immature, en- 

 cysted in stomach wall of host; plump, fusiform, pinkish in color, 

 and surrounded by black pigment; only intestine, excretory vessels, 

 and retracted appendix could be distinguished : Length, 4.5 mm. ; 

 probably belongs to this species. 



