BELEMNITES. 



261 



an internal coiled shell. The shells of Spirula Peronii La- 

 marck are rarely thrown ashore on Nantucket ; it lives upon 





Fig. 217. Pearly Nautilus, N. po/npilix. been in section showing 

 the chamoera and siphuncle. Half natural size. From Tenney's Zo- 

 ology. 



the high seas. The extinct Belemnites had, like the recent 

 Moroteuthis Verrill, a straight conical shell, the " thunder- 



Pig. Poulpe or Common Octopus of Brazilian Coast. 



bolt " fossil. Allied to Loligo and Ommastrephes, are gigan- 

 tic cuttle-fishes which live in mid-ocean, but whose remains 



