282 s. GOTO. 



tine as the common genital opening is in front of it ; vaginal 

 canal tolerably long and dividing into two when it has proceed- 

 ed a little over one-half of the distance between the vaginal 

 opening and the front end of the ovary. Testes large, about 15 

 in number, extending from the hind end of the ovary to a little 

 in front of the posterior end of the vitellaria. 



Habitat. — Gills of black-fish {Hiatida onitis). 



Loc. — Newport, R. I. 



3Hcrocotyle longlcauda n. sp. 

 (PI. XXI, fig. 30 & 31.) 



Body symmetrical, elongated, pointed at the two ends, 6 mm. 

 long, the ratio of the sucker- bearing portion to the body proper 

 being 7 : 11 ; number of suckers about 120 on either side. 

 Oesophagus moderately long ; the main intestinal branches of 

 equal length on the two sides, with numerous bifurcating, hiteral 

 branches on the inner and outer sides, except in the most 

 posterior portion extending beyond the vitellaria, the branches 

 of the inner side being much shorter than those of the outer. 

 Common genital opening a short distance in front of the hind 

 end of the oesophagus. Genital atrium very spacious, and divi- 

 sible into two portions, an anterior and a posterior, the latter 

 being less capacious ; atrial spines conical and slightly recurved, 

 arranged in two groups (fig. 31) corresponding to tlie two por- 

 tions of the atrium just mentioned, and the posterior group being 

 again divided in the median line. The spines of the anterior 

 group range in length between 13 jj- and 16 /^, but those of the 

 posterior group are much shorter, being 9 /^ or less. Ovary like 

 the anterior two-thirds of an S in shape, presenting an almost 

 straight border in front. Oviduct arising on the right side and 



