PHYLUM ANNULATA 



463 



the capsulogenous glands (p. 457), situated in the neighbourhood 

 of the reproductive organs. The sperms from the male apertures 

 of each pass along temporarily formed grooves to the rcceptacula 

 seminis of the other. 



When the ova are mature they are discharged from the ovary 

 into the cavity of the thirteenth segment, whence they pass out 

 to the exterior through the oviducts, to be enclosed in the cocoon 



eel 



a si op 



7n.es 



FIG. 364. Early stages in the development of Lumbricus. A, lateral view of flattened blastula ; 

 B. ventral view of gastrula with slit-like blastopore ; C, lateral view of later stage, blaztoc. 

 blastoccele ; blastop. blastopore ; eet. ectoderm ; en<l. endoderm ; m. primary mesoderni cell ; 

 rues, mesoclerm bauds ; iur. cell from which the primitive nerve-cord (ne. co.) takes origin ; 

 npli. cells taking part in the formation of the uephridia ; st. stomodseuni. (After Wilson.) 



(vide infra), after having being detained for a time in the 

 receptaculum ovorum. 



Development. The oosperms or fertilised ova of the E&rth- 

 worm are enclosed, together with a quantity of an albuminous fluid 

 derived from the capsulogenous glands, in a cocoon, the wall of 

 which is formed of a viscid secretion from the glands of the 

 clitellum, hardened and toughened by exposure to the air. The 



