SECT. X REPRODUCTION 147 



coelom epithelium in small groups. So also the small 

 bulgings in the epithelium in which the sperm-cells 

 develop may be considered to represent small pustules 

 containing sperm in the peritoneal wall of an Annelid 

 (see Fig. 33, /), but in this case the organs which 

 this wall originally covered, i.e. the nephridia, have 

 disappeared. 



Lastly, we repeat the fact, that in no other Crus- 

 tacean are the sexual glands segmentally arranged ; 

 one pair in each developed segment, and rudiments 

 in the more developed of the rudimentary segments. 

 The value of this fact for our argument can hardly be 

 over-estimated. 



L 2 



