2^94 Robert Thompson Young, 



structures diiferent from those mentioned elsewhere have been de- 

 scribed by PiNTNEE (1903) in the Tetrarhynchidae but a discussion 

 of these lies outside the scope of the present work. Zschokke (1888) 

 in his studies of several species of the Taeniadae and Tetrabothridae 

 has described the cuticula as varying- in diiferent species in the 

 same family. 



I wish to consider briefly the description of the cuticula given 

 recently by Minckeet (1905) in the larvae of Ligula intestinalis, 

 Schistoceplialus nodosus and the adult Moniezia expansa and Triaeno- 

 pJiorus nodulosus. This author in the figure accompanying' his article 

 depicts the cuticula as consisting* of three layers, an outer or 

 "Comidienschicht", a middle or "homogene Schicht" and a basal layer 

 of "direkt über den Insertionsstellen der Epithelzellfortsätze stehen- 

 den Grundstreifen". The outer layer is figured as equaling in thick- 

 ness the middle, while the third layer is very thin. He says (p. 405) 

 that "Ein besonderer Zusammenhang der Comidien mit den Epithel- 

 zellen . . . existiert nicht". In the "homogene Schicht" he describes 

 two kinds of canals, "Trophoporen", which at base divide to form 

 several "Trophoporellen", and "Neuroporen" connecting- basally with 

 "Neurophysen", which are synonymous with the endings of the sense 

 cells of other authors. The former he considers synonymous with the 

 pore canals of former writers. 



In my own preparations I have frequently encountered cavities 

 of varying shape and size in the cuticula ^), but the fact that they 

 have no regular arrangement whatsoever, and that in favorable 

 places in the cuticula of adult Cysticercus pisiformis I find, the 

 same as in younger stages, a continuous network of fibrillae, inclines 

 me strongly to the belief that these are merely artifacts and that 

 in this larva at least there are normally no openings in the cuti- 

 cula whatever. The erratic nature of the Golgi stain should make 

 us wary of accepting results obtained by its use, until the same 

 have been verified by many observers. 



While I am unable to demonstrate an indisputable connection 

 between the elements of the "hair" layer and the sub-cuticular cell 

 processes, the developmental history of the cuticula as described 

 above makes such a connection highly probable. In many prepa- 

 rations there is a more deeply stained layer at the base of the 

 cuticula. I find, however, that this layer varies in thickness in 



1) Especially is this true of the cuticula of the adult worm. 



