OF THE CYSTIC ENTOZOA. 83 



than that of the two higher forms ; the cyst is not divided into 

 separate parts, and the young are developed promiscuously 

 throughout its internal surface. 



In Acephalocystis armatus, the young are developed from a true 

 germinal membrane, each of the young arising as a separate cell, 

 and afterwards throwing off internally successive broods of young 

 independently. It is also distinguished from the other species 

 by the teeth which it possesses during the period of its attachment 

 to the parent germinal membrane. These teeth are generally 

 exactly opposite the spot of attachment, are quite straight, barb- 

 less, and form an irregular circlet, somewhat similar to that of Cse- 

 nurus and Cysticercus. They are lost as soon as the animal leaves 

 the germinal membrane and becomes free, and not the slightest 

 vestige of them can be seen, even upon the shreds of membrane 

 alluded to above, which at one period formed the internal mem- 

 brane of the parent sac. 



In the Medical Gazette for Nov. 22, 1844, p. 268, there is an 

 abstract of a Paper read before the Royal Medical and Chirnrgical 

 Society of London, by Erasmus Wilson, on the classification, &c., 

 of Ecliinococcus hominis. There can be no doubt that the Echi- 

 nococcus here described by Mr. Wilson, and the Acephalocystis 

 armatus are both one and the same species. The bodies de- 

 scribed by Mr. Wilson as the echinococci, and which are at- 

 tached to the internal surface of the membrane, are merely the 

 young acephalocysts either of the secondary or tertiary stages of 

 developement. They will be, as already fully described in this 

 paper, of the secondary generation, if found growing from the 

 walls of the original containing sac, and tertiary if found grow- 

 ing from the w^alls of those sacs floating free in the fluid contained 

 within the original sac. This animal is an acephalocyst, and not 

 an echinococcus. Bremser, in the atlas of his work, On the 

 Intestinal Worms of Man, calls it an echinococcus, but upon 

 false grounds, for the proper definition of echinococcus, he 

 says, at p. 294 of his w^ork alluded to :* a M. Rudolphi dis- 

 tingue les hydatides en vivantes et en non vivantes ; il regarde 



* Trait^ Zoologique et Physiologique sur les Vers Intestinaux de 1'Homme, par M. Bret^r. 

 Traduit de I'Allemand par M. Grandler. Revu et augmente de Notes par M. de Blainville. 



