TIIYLLOPODA. CLA.DOCERA. 



421 



tubes by the side of the alimentary canal. In the ovaries groups 

 of four cells are separated ; one cell of each group becomes an ovum, 

 while the rest are employed as nutritive cells for the nourishment of 

 the ovum, which increases in size and absorbs fat globules. The ovary 

 is directly continuous with the oviduct, which opens dorsally beneath 

 the shell into the brood-pouch. The testes, like the ovaries, lie at 

 the sides of the intestine and are continuous with the vasa def erentia, 



FIG. 331. "DapTinia. C, Heart the slit-like opening of one side is visible ; D, alimentary 

 canal; L, hepatic diverticulum ; A, anus ; G, cerebral ganglion ; O, eye ; Sd, shell gland ; 

 Br, brood-pouch beneath the dorsal reduplicature of the shell. 



which open to the exterior ventrally behind the last pair of appen- 

 dages or at the extreme end of the body, the openings being some- 

 times situated on small slightly protrusible prominences. 



The smaller males usually appear in the autumn ; they may, however, 

 also be present at any other time of the year, and, as recent investi- 

 gations have proved in a tolerably satisfactory manner, always when 



