DEVELOPMENT OF THE SPERMATOZOA. 



159 



known the proper degree of concentration of the fluids to be 

 applied, I have never seen coiled-up tails. 



Kolliker believes that, in the formation of the tail, the 

 nucleus, as it develops, is protruded from one pole as a delicate 

 tube. I have frequently seen these nuclear appendages in the 

 seminal corpuscles of the Bull, in a one-half per cent, solution of 

 common salt, and in solutions of chromate of potash ; with 

 Henle, I regard them as the remains of the sperm cells. 



Fig. 187. 



Fig. 187. Spermatozoa of the Bull, with nuclear appendage. 



The development of the spermatozoa of the brown land-frog 

 must be regarded as highly remarkable, and as quite excep- 

 tional amongst the Vertebrata. After Remak, Ankermann, 

 and Kolliker had investigated this subject, it has recently 

 been again examined by Neumann. It would lead us too far to 



Fig. 188. 



Fig. 188. Development of the spermatozoa of the Rana temporaria. 



recapitulate the views that have been hitherto advanced 

 respecting it, and I shall only give briefly the results of my 

 own observations. The seminal corpuscles of the Rana tem- 

 poraria develop in a manner exactly similar to those of the 



