NAUTILUS. 



improbable, because it would require the exertion of such 

 a kind of instinct and muscular action as must be entirely 

 useless to it, it would certainly be very little, if at all dis- 

 posed, to leave the pursuit of its prey in order to take a 

 pleasant sail on the surface of the ocean. What we 

 have here stated is on the supposition that its animal is 

 cephalopodous, (and we think there is much reason for 

 adopting that opinion), and it is well known that the 

 cephalopoda are exceedingly voracious ; we cannot there- 

 fore suppose that its time would be otherwise occupied 

 than in pursuing the bent of its natural dispositions. If 

 any of our readers, desirous of ascertaining the probabi- 

 lity of this animal sailing about on the surface of the 

 ocean, will place one of the shells in a vessel of water 

 sufficiently deep, it will be found to swim exactly in the 

 position in which we have drawn it in our plate, in which 

 position if the animal were in it and partly surrounding 

 it, as it most probably does, its head and body would be 

 entirely covered by the water, and no part of the edge of 

 the shell could be visible; thus supposing the shell to 

 resemble a boat or sailing vessel, it could naturally only 

 swim with its stern upwards; and to keep its gunnel above 

 water it would require ballast, and the nicest possible 

 balancing: in fact it appears to us that neither the Nau- 

 tilus nor the Argonaut could possibly swim about with 

 their shells so placed as to resemble a galley or skiff. 



Of recent Nautili three or four species at most are 

 known, which we believe to be all inhabitants of the Pa- 

 cific and Australian, possibly extending also to the Indian 

 ocean. The fossil species, which are more numerous, are 

 found not only in the tertiary beds, as the London clay 

 and the Calcaire grossier, but also in several of the beds 

 belonging to the secondary class, particularly among the 

 Oolites, and as low as the Mountain Limestone. 



Shell univalve, not attached, suborbicular, convolute, 

 with contiguous volutions, in which respect it differs essen- 

 tially from !Spirula, whose volutions are separated; 

 chambers numerous, the septa transverse, concave out- 

 wardly, perforated by a siphunculus, and having their 

 margins entire: aperture very large. Lamarck says in 



