146 CONCHOLOGY. 



nated, longitudinally subinvolute in the same plane; aperture 

 very wide, symmetrical, complete, square anteriorly, slightly mo- 

 ditied by the turn of the summit, and provided o-n each side with 

 aa earlike appendage having thick and smooth edges. Inhabits 

 the Mediterranean. Three species. 



Argonauta argo. Argonauta tuberculosa. 



A. nitida. 



2. Genus Carinaria. PI. XII. 

 minimal. Body elongated, prolonged behind the nucleus into a 

 veritable tail edged at its extremity by a vertical fin ; head suffi- 

 ciently distinct, two long conical tentacula ; two sessile eyes ; 

 the organs of respiration and the nucleus entirely ehveloped in a 

 mantle with lobed edges. 



Shell. Very thin, symmetrical, a little compressed, without 

 spire, but with the summit a little reflexed posteriorly ; aperture 

 oval and entire. Inhabits the African, Mediterranean, and Aus- 

 tralian seas. Three species. 



Carinaria vitrea. Carinaria fragilis. 



C. cymbia. 



