10 ART. 7. — I. IJIMA. 



the sides and broad at both ends which show each a depression 

 due to invagination of terminal parts (figs. 2d, 9, 12). When 

 the head is withdrawn to the utmost degree it may be difficult 

 to distinguish that end from the hind end, and moreover it may 

 happen that such a worm is but a fragment constricted off from 

 the hind parts of the Plerocercoid and is thus devoid of the parts 

 which may be called the head. 



The simple Plerocercoid I regard as the original form of 

 the larva, which, as will soon be shown, may acquire a widely 

 different shape in a later larval stage. I regard it also as the 

 form the larva would be in just before it begins strobilation after 

 introduction into the final host. 



Now a remarkable fact about the present Plerocercoid is 

 that it is capable, at a certain advanced stage of its intra- 

 capsular life, of proliferating by a process of budding coupled 

 with the before mentioned division of the body. We seem to 

 have here to do with a ]3rocess of which counterparts are known 

 in the well known Echinococcus and Cœnurus as well as in 

 Cysticercus longicollis and certain Cysticercoids, but which presents 

 some peculiar features standing probably in connection with the 

 Plerocercoid form of the proliferating larva. So far as my know- 

 ledge goes, a budding Plerocercus or Plerocercoid seems not to 

 have been known before, at least not with certainty. 



Among a large number of the specimens freed from capsules, 

 those bearing from one to several buds or supernumerary heads 

 in addition to the original terminal head of the simple Plerocer- 

 coid, are of quite common occurrence. The buds are found only 

 on the larger-bodied specimens and therefore on those taken 

 from the larger capsules. This shows that the budding takes 

 place only after the Plerocercoid has grown to a certain size. 



