ON A NEW CESTODE LARVA PARASITIC IN MAN. 11 



Facts observed warrant the statement that the worms in the early 

 period of encystment, and therefore when still small and solitarily 

 confined in the cyst, are simple Plerocercoids with the terminal 

 head only. The budding may occur in any region of the broad 

 posterior parts, but not on the narrow retractile head. 



The specimens of figs. 4, 6 and 14 bear each a bud in dif- 

 ferent states of contraction and looking much like a lateral branch. 

 The specimen of fig. 5 is in possession of two unmistakeable su- 

 pernumerary heads; in this specimen, as also in that of fig. 4, 

 the buds are situated plainly on lateral edges of the flattejied 

 body. This situation of the buds may in fact be the rule in the 

 earlier period of proliferation ; but as they increase in number 

 and the mother-body assumes an irregular shape, the rule loses 

 applicability in that they then appear to arise from quite inde- 

 finite parts of the external surface. Of specimens with numerous 

 buds I have represented two in figs. 7 and 8. The original of 

 the latter figure bore considerably over a dozen thread-like buds. 



The structures referred to above as buds, difier in no way, 

 except in situation and perhaps also in size, from the original, 

 terminally situated Plerocercoid head. They manifest exactly the 

 same shape and movements as the latter. The numerous buds in 

 the specimens of figs. 7 and 8, at the time of killing, were almost 

 all in vermiform motion while the mother-piece showed little or 

 no movement. I think there can be no doubt whatever that the 

 buds are to be looked at in the light of heads, secondarily pro- 

 duced but quite equivalent to the single terminal head. In the 

 end it is quite immaterial to distinguish this original head from 

 those formed later by budding. 



Since now the larva is capable of transverse fission, it follows 

 that the heads, irrespective of the manner of their origin, may 



