CEPHALOPODA. 



437 



. (479.) A still more interesting group of CEPHALOPODS, and 

 one which in former periods of the world has been extensively 

 disseminated, inhabited chambered shells ; but of all the varied 

 forms of these creatures, whose remains are so abundantly met with 

 in a fossil state, and known by the names of Ammonites, Belem- 

 nttes, Nummulites, Sec. two species only have been found to be at 

 present in existence, the Spirula, an animal as yet imperfectly 

 known ; and the Nautilus Pompilius, of which the only specimen 

 obtained in modern times* has been the subject of a monograph 

 by Professor Owen, who has most completely investigated its gene- 

 ral organization and relations with other families of the Cephalo- 

 poda. The shell of the Pearly Nautilus (N. Pompilius) is extreme- 

 ly common, and may be met with in every conchological collection, 



Fig. 205. 



notwithstanding the extreme rarity of the mollusk that inhabits 

 it ; a circumstance, perhaps, to be explained by the fact that the 



* For this invaluable addition to zoological knowledge science is indebted to George 

 Bennet, Esq. who obtained the living animal near the island of Erromanga, New 

 Hebrides. " It was found in Marekini bay, floating on the surface of the water not 

 far distant from the ship, and resembling, as the sailors expressed it, a dead tortoise- 

 shell cat in the water. It was captured, but not before the upper part of the shell 

 had been broken by the boat-hook in the eagerness to take it, as the animal was sink- 

 ing when caught." Mr. Rennet's Journal. 



