22 



ENTOZOA. 



3 and 4), all that need here be said is that they usually present an 

 oval figure, having a yellow-brown chorion, a more or less seg- 

 mented yelk, and a transverse line near one pole of the shell which 

 serves to indicate the point at which their lid-like extremity be- 

 comes detached after the subsequent maturation of the embryo. 

 One of the eggs represented in the plate has been artificially 

 ruptured in this situation. I may also mention the circumstance 

 that I have found (as shown in the centre of fig. 1) two of the 



1^4 



f 



Fig. 4. — Distoma Bosch, Cobbold. — From the oral cavity of au American snake {Coluber). 



X 10 diam.— Original. 



flukes sexually combined — a fact of great significance in relation 

 to the probably erroneous notion entertained by some, that the 

 hermaphroditic flukes are capable of self-impregnation. 



Develojjment — Ever since Steenstrup's discovery that the 

 cercarise found in the bodies of water snails were only larval 

 flukes, a peculiar interest has attached itself to this subject ; for 

 not only were the facts which he elicited novel in themselves, but 

 they formed a basis for the enunciation of that interesting "law of 

 alternate generation" with which the great Danish naturalist's 



