76 



THE EVOLUTION OF SEX. 



the cirripedes are hermaphrodite ; but among the barnacles 

 proper, — the stalked forms, which are nearer the ancestral type, 

 — separate sexes sometimes occur. On the females of a few 

 of these, pigmy males, like those found upon hermaphrodites, 

 also occur. These pigmy males, whether on females or herma- 

 phrodites, are not only dwarfish, but are very often degenerate, 

 sometimes wanting (according to Darwin) both alimentary 

 canal and thoracic legs. Some of them, in fact, are little more 

 than parasitic testes. 



(i.) The original state of affairs in this case was probably the ordinary 

 crustacean condition of separate sexes. (2.) The males, as in some of the 

 "water-fleas" or copepods, tended to be smaller, — smaller indeed to a 



Myzostomata : — A hermaphrodite (i) and a pigmy male (2). — Itoiii Naiisen. 



vanishing point, — while the females became more and more sluggish, and 

 settled down. (3.) In the genera Alcippe and Crypiophiahis^ in the species 

 Iblaciii/iiningii and Scalpelbuii oniattiiii^ we find true females, with attached 



