SOME MAMMALIAN TAPEWORMS. 641 



absent altogether, beino- really retracted almost completely within 

 the head ; there were four little tags only protruding from the 

 anterior exti'emity. This scolex I have examined further by 

 transverse sections. The second worm showed only two cup-like 

 suckers, with their cavity diiected upward as in other species of 

 Bertiella. One of these is distinctly larger than the other, and 



Text-fig. 152. 



r ^ '' 



Sertiella cercopitheci. 



Transverse section through scolex. 



S. Sucker. P. Pigment-sheath of the same. 



I presume that the remaining two were completely retracted 

 within the head. In a series of very nearly accurately transverse 

 sections through the head of the first individual, the earliest 

 sections showed four equidistant grooves lined by a continviation 

 of the thick cuticle of the scolex, which expanded towards the 



