OF CEPHALOPODA. 213 



that of Spirula, another ten-armed cephalopod, which has a 

 highly organized, cross-partitioned, spiral shell, very much like 

 that of the common Nautilus, but placed in exactly the reverse 

 position from the latter. The shell of the Nautilus occupies the 

 same relative position as that of the Snail, whilst the shell of 

 the Cuttle-fish, Squid, Spirula, &c., is placed upon the opposite 

 side, i. e., the lower side of the body.* 



* Looking at Nautilus from this point of view, the highly muscular " hood " 

 falls very naturally into the place of a creeping disc, or foot ; and in this respect 

 it agrees in position with what the old Hollandish naturalist Rumphius ascribes 

 to it when the animal is creeping with the shell above the body, like that of a 

 Snail. 



