AN ESSAY 



UPON 



THE HUMAN CESTOIDS, 



PART I. 



BELONGING to the order of Sterelmintha, of the sub- 

 class Entozoa, these cestoids are capable of division 

 into two genera ; viz., Tsenia and Bothriocephalus. 

 Formerly a third was added, i.e., Echinococcus ; but, 

 as this has lately been discovered to be a tsenioid em- 

 bryo, it is entitled to no generic distinction. The 

 order of Sterelmintha is distinguished from the other 

 order of this sub-class, the Ccelelmintha ; inasmuch as, 

 in its members, the intestine is in some cases wanting, 

 in others vascular ; while, in the second (the Coelel- 

 mintha), the intestine is in a distinct cavity ; the first 

 being identical with the Vers Intestinaux Parenchy- 

 mateux, the second with the Vers Intestinaux Cavi- 

 taires of Cuvier. It is my intention simply to review 

 the parasites of the first order ; to study the anatomy, 

 embryology, &c., of the two genera; the pathological 



