SPIRULA. 181 



his head and all his tentacles, and spreads them upon 

 the water, the poop of the shell rising above the sur- 

 face ; but at the bottom he creeps in the reverse position, 

 with his boat above him, and his head and tentacles on 

 the ground, making a tolerably quick progress. It is 

 upon the ground that he chiefly keeps himself, creeping 

 sometimes into the nets of fishermen ; but after a storm, 

 as the weather becomes calm, troops are seen floating 

 on the water, being driven up by the agitation of the 

 weaves ; whence it may be inferred, that they congregate 

 in troops at the bottom. Their sailing, however, is not 

 of long continuance, for having taken in all their ten- 

 tacles, they upset their boat, and so return to the 

 bottom." 



With regard to the genus Spirula^ the shell is con- 

 cealed under the mantle, at the back part of the body ; 

 it is spiral, but the whorls are separated from each other, 

 instead of being contiguous : internally it is divided into 

 chambers, perforated by a siphon ; and the last turn 

 of the spire is prolonged to a straight line. Our infor- 

 mation respecting the animal itself is very limited. It 

 appears to form the link between the ordinary cepha- 

 lopods and the pearly nautilus. 



Here then we close our cursory review of the living 

 moUusca — the multiform mollusca — a division of the 



