The Histogenesis of Cysticercus pisiformis. 203 



second a nucleus, Avhose nuclear membrane is barely outlined and 

 which contains two or three exceedingly minute granules of chro- 

 matin. I have observed similar instances in which basal plate and 

 ciliate process w^ere well formed while the nucleus was still in a very 

 early stage of development. Figs. 18 and 19 afford additional 

 grounds for this view, for here one finds basal plate and ciliate process 

 developed apart from any nucleus. 



This belief is strengthened by a study of tw^o figures in an 

 article by Bugge, to which reference will be made later, namely 

 figs. 20 and 24. In the first of these, one sees three developing 

 flames with the basal plate and ciliate process apparently differ- 

 entiated out of the cytoplasm of the common cell mass. Nuclei 

 are indicated above these, but so indefinitely that, from the figure, 

 it is impossible to say whether the cells are nucleated as yet or 

 not. This figure strongly suggests the probability that the basal 

 plates and ciliate processes have arisen as chromatin difterentiations 

 of the unmodified, potentially nuclear cell mass, independently of 

 any pre-existent nucleus. And in fig. 24 is suggested the origin of 

 basal plate as a chromatic difi'erentiation of the cytoplasm simulta- 

 neously with the differentiation of the nuclear chromatin. In my Figs. 25 

 and 27 one sees the intimate contact, if not actual union of nucleus 

 and basal plate in some flames. The fact, however, that the nucleus 

 is usually separate from the basal plate, and often by a considerable 

 distance (Fig. 24) renders the latter condition improbable. The flame 

 cells usually develop in groups of tAvo to four, but it is highly 

 probable that at least in the early stages'of the larva they occasion- 

 ally develop singly. On this point I cannot offer any positive 

 evidence however. A group of four developing flame cells is shown 

 in Fig. 40. 



The capillaries are developed intra-cellularly within pre-existent 

 parenchyma strands, the funnels being always developed from the 

 cytoplasm of the flame cell itself^) This intra-cellular development 

 of the capillaries is shown in Fig. 38. Here one sees a part of a 

 well developed capillary, c, wdth its cell, cc, opening into the devel- 

 oping excretory duct at oc. Another capillary, c', is shown devel- 

 oping here in connection with the capillary cell, cc\ and the flame 



1) The intra-cellular character of the capillaries is evident in that 

 part which is proximal to the flame cell. Distally it is impossible to say 

 whether their lumen is intra- or inter-cellular. 



