POSTSCRIPT. 517 



longitudinal canal of the Wolffian body (l.c}. From the latter 

 are seen passing off the successive tubuli of the anterior seg- 

 ments of the Wolffian body in connection with which Malpighian 

 bodies are typically present, though not represented in my 

 diagram. 



Postscript. 



It was my original intention to have given an account of 

 the development of the generative organs. In the course, how- 

 ever, of my work a number of novel and unexpected points 

 turned up, which have considerably protracted my investiga- 

 tions, and it has appeared to me better no longer to delay the 

 appearance of this monograph, but to publish elsewhere my 

 results on the generative organs. In chapter VI. p. 349 et seq. 

 the early stages of the generative organs are described, but in 

 contemplation of the completion of the account no allusion was 

 made to their literature, and more especially to Professor 

 Semper's important contributions. I may perhaps say that I 

 have been able to confirm the most important result to which he 

 and other anatomists have nearly simultaneously arrived with 

 respect to Vertebrates, viz. that the primitive ova give rise to both 

 the male and female generative products. 



