STUDIES OS THE ECTOPARASITIC TrEMATOOES OF JAPAN'. 187 



the body, and unite in the median line at the level of the hinder end 

 of the anterior third of the ovary. The testes occupy a little less than 

 one quarter of the whole length of the body and are situated behind the 

 ovary ; they are large and are about 23 in number. The two main 

 trunks of the intestine send out lateral branches both inwards and out- 

 wards ; the left trunk is longer than its fellow, and extends beyond 

 the vitellai'ium into the caudal disc, while the right trunk ends with 

 the vitellai'ium. The caudal disc is about ^ tlie length of the whole 

 body, and is narrow. Posterior suckers about 25 on each side ; 

 breadth 0.045-0.08 mm. 



Habitat — Gill of Sebastes sp. sp. (Jap. Mebaru and Kin-mebaru). 



Locality — Mitsugahama (Prov. lyo). 



Date— August 1889. 



2. Microcotyle sebastis, n. sp. 

 (PI. I, figs. 2 & 3 ; PJ. Ill, fig. 1 ; PI. IV, figs. 1, 4, & 5.) 

 Body about 5.5 mm. long, slender ,^ symmetrical. Anterior sucker 

 with a septum. Common genital opening a little in front of the point 

 of bifurcation of the alimentary canal ; atrial spines conical, slightly 

 curved, the longest about 0.017 mm. Ovary long, situated at about 

 the middle of the entire length of the body ; the anterior portion is A- 

 shaped and the posterior portion somewhat S-shaped with its left 

 anterior end continuous with, and folded on, the leg of the /\ ; the 

 hindmost terminal portion being folded many times on itself. Vaginal 

 opening single, median, and dorsal, situated about thrice as far in front 

 of the anterior end of the ovary as it is behind the common 

 genital opening. The vaginal canal continues single for about half 

 way towards the anterior end of the ovary, then divides, and the 

 two ducts thus formed, after traversing about one-third their way 

 towards the ovary, become continuous with the paired yolk-ducts.- 



