Carinaria

Carinaria, a genus of free-swimming marine snails (Gasteropods) belonging to the small order Heteropoda. They are beautiful transparent animals, with a thin brittle shell (like a miniature paper nautilus) covering only the visceral hump and leaving even the gills exposed, and with the ventral surface or 'foot' pulled out into a movable tail, and bearing anteriorly a leaf-like swimming fin, provided with a sucker. The head protrudes far in front of the soft body, and bears a pair of tentacles. The organs and their working can be beautifully seen within the transparent body. The sexes are separate. Carinaria is represented by eight species in warmer seas. They swim back downwards, and feed voraciously on other marine animals, such as jelly-fish and pteropods. The common Mediterranean species, C. mediterranea, may be over six inches in length, has a violet proboscis and a rose-coloured foot, and is a beautiful transparent snail. The neighbouring genus Pterotrachea has no shell.