STUDIES ON THE ECTOPARASITIC TREMATODES OP JAPAN. 203 



he included in it tlie fovms which I hold to require separation into two genera. 

 The genus Octocotyle I propose to characterise as follows : 

 Body lanceolate, usually thick'^; anterior end obtuse- 

 ly triangular, posterior end rounded. With a single 

 pair of ellipsoidal anterior suckers inside the mouth, 

 and with four pairs of posterior, somewhat bean-shaped 

 suckers on the ventral side at the posterior end of the 

 body. With one or two pairs of hooks between the last 

 pair of posterior suckers. Without a vagina. With a 

 penis consisting of a median, cup-shaped body with a 

 thick wall, which is perforated by the vas deferens, 

 and an accessory, bean-shaped body attached to it 

 on each side; all three bearing hooks on their inner 

 surface. 



1. Octocotyle major, n. sp. 

 (PI. IX, figs. 1-6.) 

 Bodiij lanceolate and thick^\ about 4 mm. long, the anterior part 

 free from the vitellarium very short ; posterior suckers small, being 

 about'' 0.045 mm. x 0.038 mm., and ai-ranged close to the lateral 

 margin of the body. With only one pair of large UooTis between the 

 hindmost pair of suckers. The hook with a process at the middle 

 of its length, its distal half enclosing a narrow cavity within (PI. IX, 

 fig. 2), and its proximal portion striated lengthwise ; the latter 

 appearance being due to the presence of longitudinal furrows on its sur- 

 face: leno'th of the hook 0.1 mm., the curvature not taken into account. 



1). The term " depressum " I find to be wholly inappropriate to the species observed by me. 



2). In the figure the body seems flatter and broader than it is in reality, owing to the 

 pressure ot fhe cOTer-glass to which the specimen was subjected when killed. 



3). The length of the posterior sucker has been measured parallel to the arms of the 

 tJ-shaped chitinous piece, and its breadth at right angles to the same. 



