12 



ENTOZOA FOUND IN MAN. 



worms in either soft or hard water, and of the pre- 

 sence of a certain number of imperfect cestoid worms 

 in the parenchymatous organs, or in the closed 

 cavities, of animals. 



Section A. Tsenise in the Larval Condition. (Vesi- 

 cular Form. Vesicular or Cystic Worms). 

 "Genera C?) Hydatis, and Echinococcus grouped 

 together." First Phase of Development ; Hydatid 

 (Acephalocyst). 



This is generally a spherical, or oval, vesicle, of 

 very variable size, ranging from that of a piu's head 

 to that of the head of a foetus at the full term of 

 gestation ; it encloses a limpid fluid ; it has thin 

 walls, which are not contractile, and are composed of 

 a homogeneous, elastic, fragile, transparent, whitish 



rig. 2} 



* Explanation of Figure 2.— Hydatid found in man. 1. A 

 fragment of the natural size ; at its edge are sliown the layers of 

 which it is composed ; on the external surface are several hydatid 

 germs, of different periods of development. 2. One of the germs 

 flattened and magnified forty times ; it is formed, like the parent 

 hydatid, of stratified layers ; the germinal membrane is not yet 

 developed in its central cavity. 



