The Histog-enesis of Cysticercus pisiformis. 225 



The cell bodies become more or less sharply delimited from the 

 surrounding parenchyma, with which, however, as well as with each 

 other, they remain in organic union. Theii" peripheral processes 

 remain thruout in connection with the cuticiila and, as already 

 mentioned in the study of the latter, in places where the stain is 

 not too deep, they appear to pass completely thru the cuticula, not 

 terminating as generally described, in its basal portion. Obviously, 

 in a tissue whose elements are as irregular and as closely packed 

 together as thej^ are in the sub- cuticula, it is verj^ difficult to 

 determine accurately the relations of the different elements to each 

 other. I have, however, satisfied myself beyond question that, in 

 the adult as well as embrj'onic condition, the sub- 

 cuticula of Cysticercus pisiformis and Taenia serrata 

 is a syncytium of cells which anastomose with each 

 other and with the subjacent parenchyma. An anastomosis 

 between two adjacent cells is shown in Fig. 50, which represents 

 three sub-cuticular cells and a neuro-muscular cell from the neck 

 region of Cysticercus pisiformis, while a similar anastomosis 

 of sub-cuticular cells in Taenia serrata is shown in Fig. 49. 



An interesting feature of the development of the sub-cuticular 

 cells, which is seen very plainly in tracing it thru the different 

 stages from the bladder anteriorlj-, is the great increase of 

 staining capacity of the cell body, w^hereby a distinction 

 between cytoplasm and nucleoplasm is gradually lost, 

 the cell finally appearing as a solid mass of deeply- 

 staining substance. It will be more satisfactory to postpone 

 further consideration of this question until the study of cytogenesis 

 is taken up. 



The sub-cuticular cells are lacking in the suckers. 



The development of the sub-cuticular cells by a modification of 

 ordinary parenchyma cells, such as is described above, has been 

 stated briefly by Leuckaet (1879—1886). 



The Epithelial Question. It may appear to some super- 

 fluous to undertake here the resurrection of a question so carefully 

 laid away to rest by Blochmann (1896) but conjured up by several 

 investigators since that time in the hope of adding something to 

 the epitaph written by him in his "Epithelfrage", with the result, 

 however, of comparatively little addition to Blochmann's work. 

 In view of the fact, however, that no investigator has as yet made 

 any thoro study of histogenesis in the Cestodes, and further, since 



