CHAP. IV.] 



THE VOYAGE HOME. 



197 



stome are mucli fewer. The ovaries, which in C. papillata 

 have the walls loaded with large expanded calcareous plates, 

 contain only a few small branched spicules ; and the calcareous 

 bodies in the wall of the intestine are small and distant. The 

 perforations in the ovarial plates in the female are somewhat 

 larger than in C. papillata ; and the ripe ova in the ovary ap- 

 pear to be considerably larger. 



Fig. 42.— Ci'dam wM^na;, Wtville Thomson. Balfour Bay, Kergueleu Islaud. Natural size. 



The eggs, after escaping from the ovary, are passed along on 

 the surface of the test toward the mouth; and the smaller 

 slightly spathulate primary spines, which are articulated to 

 about the first three rows of tubercles round the peristome, are 

 bent inward over the mouth, so as to form a kind of open tent, 



