STUDIES ON THE ECTOPARASITIC TEEMATODES OF JAPAN. 9() 



and the circular. The radial fibres must again be divided into two 

 groups. In one they are direct conthiuations of the longitudinal 

 fibres of the body, and on entering the sucker diverge irregularly more 

 or less in all (Urections, and are inserted, some to the elevation that 

 forms the wall of the central polygon, others t(j the periphery of 

 the sucker. The other group of radial filtres includes those fibres 

 which start from the central p(dyg(jn, and passing along the radial 

 elevations, are inserted in the periphery of the sucker. The traiisvcrsc 

 or dorso-ventral fibres merely traverse the thickness of the sucker, and 

 are inserted into the basement membrane. Like the dorso-ventral fibres 

 of the other parts of the body, they ramify into a number of small 

 branches t<3wards their ends. The circular fibres are present only 

 on the dorsal side; they are arranged in circles concentric with the 

 circumference of the sucker, and are comparatively few. T'he inter- 

 spaces between the muscular fibres are filled by a connective tissue 

 similar to that of the body (l?l. XIX, fig. G). 



Moyiocotylc — Morphoh^gically speaking there is no anterior 

 sucker in this genus, but physiologically speaking there is. The 

 dorso-ventral ;is well as the circular fibres of the body, namely, are 

 scrongly developed at the anterior end around the mouth (IM. XVIII, 

 fir>-. 4), so that the arrangement of muscular fibres is very similar to 

 that which obtains in the anterior suckers of nckocot ijle and of the 

 distomes. There is even a sort of marginaJ membrane on the ventral 

 lip (PI. XN'lIl, fig. 4, a). That this anterior portion acts as a sucker 

 is beyond doubt ; for I have observed the W(jrm execute an active leech- 

 like Locomotion l)y alternately attaching and deùicliing the m<niih and 

 the posteri(3r sucker. In fact, the structure here described is a prelim- 

 inary step to the formation of such antericrr sucker as that of 

 (Jiicliocodjlc and the distomes ; the ordy difference being that in the 

 latter, the sucker has been distinctly separated from the surrounding 



