BY J. P. HILL. 57 



a network around tlie pulsatile vesicle. The larger vessels he 

 terms the descending trunks, and the smaller the ascending, 

 Monticelli confirms* Fraipont's description as to the difference in 

 size of the vessels and also as to the mode of termination of the 

 vessels.! Pintner,;}: on the other hand, maintains that all the four 

 canals in the young forms terminate in the contractile caudal 

 vesicle, and such is the condition in the Cysticercus under consi- 

 deration. In sections, the larger descending (Fig. 3, d. v.) and 

 the smaller ascending canals (a.v.) can be readily distinguished, 

 two on each side. They differ not only in size but in the thickness 

 of their walls. Both are lined by a cuticular membrane, which, 

 however, is thicker and much more distinct in the case of the 

 smaller ascending canal. Posteriorly the two vessels on each side 

 unite with each other, then pass inwards and backwards to open 

 into a short terminal canal which communicates with the exterior. 

 The terminal canal is lined by a very definite cuticle, which when 

 traced back is found to grow thicker and to become continuous 

 with the external cuticle of the Cysticercus. 



Structure of tJie cuticle and the subcuticular layer. — The cuticle 

 (Figs. 5 and 6) consists of a thick layer of uniform depth, which 

 with cochineal shows a differentiation into an outer thicker layer 

 and an inner thinner more deeply staining layer. The external 

 surface is smooth, no hair-like appendages being present, as 

 Monticelli§ describes for Scolex polymorphus. 



As Leuckart describes || for Cestodes generally, there is, imme- 

 diately below the cuticle and in close contact with it, a thin layer 

 of circularly disposed elastic fibres (Figs. 5 and 6, c. /) ; internal 

 to this circular layer is, in transverse sections, a layer of bright 

 refractive bodies (Fig, 5, I. f.), separated from each other by inter- 

 spaces. They represent the transverse sections of a layer of 



* Loc. cit. p. 124. 



t Zoc. cit. p. 127. 

 X As quoted by Monticelli. 



§ Loc. cit. p. 133. 

 "Parasites of Man," p. 290. 



