20 AET. 7. 1. IJIMA. 



Another, much less strongly developed system of the paren- 

 chymal musculature consists of fine muscular fibers which run 

 singly, leaving wide spaces between, in various directions but 

 mainly in the transverse plane of the body. In the narrow an- 

 terior parts (the head), as seen on cross-sections (fig. 16), there 

 is observable a tolerable regularity in the arrangement of the 

 fibers in that a set of them runs in an approximately transverse 

 direction while another takes a dorso -ventral course. In the 

 thick posterior parts (fig. 17), all the fibers run in quite an ir- 

 regular manner, which fact is probably largely due to the crowded 

 occurrence, in this region, of the wide excretory vessels and of 

 the longitudinal muscular bundles. Transverse muscles in a con- 

 tinuous layer, dividing the parenchyma into cortical and medullary 

 zones, do not exist. 



With respect to the nervous system, all that I have seen is 

 limited to the following facts. A pair of nerve trunks {n., fig. 

 16) run in the usual position ; they were observed with distinct- 

 ness only in the anterior parts of the body. They seemed to unite 

 at a position close to the tip of head. In the thick posterior 

 parts of the body, they were not at all distiuguishable. 



Taken all in all. Pier ocei'co ides proUfer shows a far-reaching 

 structural agreement, especially in the musculature and the ex- 

 cretory system, with the Bothriocephalid larva Sparganum of 

 DiESiNG, as well as with Cobbold's Ligula mansoni so-called, 

 which was provisionally referred to Botkriocephalus by Leuckart. 

 Indeed, it may be admitted to be nearly certain that the worm 



