o44 LKWIS IIENTtY GOUGH. 



no SLibcuticula in the suckers, the cuticnla of the suckei's 

 must arise independently of the subcuticula. 



Unfortunately neither Rossler (1902) nor Young (1908) 

 has made any observations concerning- the development of 

 the suckers. Leuckart ('Parasiten des Menscheu,' 2nd edition, 

 vol. i, p. 445) states that their development commences 

 by the formation of four hemispherical depressions of the 

 cuticnla in the substance of the " Kopf zapf en,"repi'esenting 

 the cavities of the suckers, and that the radial muscles arise 

 out of the subcuticular cells. Glaser (1909) finds the suckers 

 ai'ising somewhat differently, already before the subcuticula 

 is formed, at least he avoids using the term "^ subcuticula." 

 Leuckart considers that the fact of the development of 

 muscles out of the subcuticular cells of the suckers is evidence 

 that the subcuticula has nearer affinity to the musculature 

 than to the epidermoidal apparatus. In discussing the sub- 

 cuticula I will have to show that the subcuticula of the 

 proglottids stands in very close relationship to both the 

 dorso-ventral and to the transverse muscles ; Leuckart's 

 observation of the development of the radial muscles out of 

 subcuticular cells would contain nothing very remarkable, as 

 the subcuticular cells are actually muscle-elements. 



If, as according to Blochmann, the cuticnla is a product of 

 an epithelial layer, and the subcuticula is that layer, then no 

 cuticnla can exist where there is no subcuticula. There is, 

 however, no subcuticula in the suckers, and yet the suckers 

 are clothed with a cuticnla ; the subcuticula cannot therefore 

 be the epithelium producing the cuticnla. 



Cuticnla with no underlying subcuticula is also to be found 

 in older portions of the strobila, in segments where the 

 paruterine organ is fully developed ; but here we have not to 

 deal Avith primary but with secondary conditions. In the 

 anterior portion of the strobila the dorsal and ventral surfaces 

 of the segments are more or less parallel to each other 

 (fig. 43) ; proceeding distally we find tluit the segments are 

 broader at their posterior than at their anterior end, the 

 strobila appearing serrated on longitudinal sections. Examina- 



