CESTOIDEA. 29 



The head of the bothriocephalus assumes different 

 forms, owing to the great contractility with which 

 it is endowed, but it is always readily distinguishable 

 from that of the taenia. The rings, when separated 

 from the head, may also be very easily distinguished 

 from those of the taenia, by the absence of a genital 

 pore at the border, by the dark-coloured central 

 thickening which has given rise to the comparison of 

 the chain of rings of the bothriocephalus to the 

 spinal column, and by the other characteristics of 

 the taenia which have been already given. 



The fecundity of the bothriocephalus, like that 

 of the cestoid worms generally, is enormous. Eschricht 

 has counted, in a single specimen, ten thousand rings, 

 and reckoning at the rate of a thousand eggs for 

 each ring, which is below the average, this would 

 amount to ten millions of eggs from one bothrio- 

 cephalus alone. 



The ovum of the bothriocephalus is of large size ; 

 Dr. Davaine states that he has never been able to 

 discover an embryo within it, but that, accordmg to 

 a drawing made by Schubart, of Utrecht, the embryo 

 is cihated, and armed with six hooks. 



The bothriocephalus latus exists in the small 

 intestines in man. 



