UNIVALVE SHELLS. 51 



The shells composing the genus Bulla inhabit the ocean, lakes^ 

 rivers, and ditches. The marine species are found a few inches undei 

 the sand. Some of the species may be frequently taken alive in little 

 pools, between high and low water-mark, in which they are often seen 

 sporting, with a very rapid motion, in the sunbeams. 



The animal inhabiting the Bulla is considerably too large for its 

 shell, and cannot conti-act itself wholly within it, as most other animals 

 which have a testaceous covering can do. 



Genus 23— VOLUTA. 



Animal a Limax; shell single celled and spiral; aperture 

 without a beak and somewhat effuse ; pillar twisted or 

 plaited, generally without lips or perforation. 



Linnaeus divides this very extensive genus of shells into five distinct 

 famihes : *aperture or opening entire ; **somewhat cylindrical and 

 emarginate ; ***obovate, effuse, and emarginate ; **«*fusiform ; 

 •««*«ventricose, spire papillary at the top. 



Valuta episcopalis — The Episcopal Voldta. Plate 

 VIII. fig. 29. (Mitra episcopalis, Lamarck.) Emargiiiated, 

 smooth, margin of the volutions entire; lip denticulated; 

 columella with four plaits. Five inches long. Inhabits 

 the Indian ocean. Variously spotted with orange. 



Vobita Oliva — The Olive Voluta. Plate II. fig. 7- 

 (Oliva, Lamarck.) Shell smooth and glossy; spire re- 

 flected at the base ; pillar with four plaits ; clouded, or 

 covered with zigzag or waved lines of a pale brown colour. 

 Found in the Indian seas, in endless varieties of colours and 

 markings. 



A Apex, I front, n outer lip, z plaits of the pillar-lip or columella. 



The Volutes have only been found in the ocean, and are most com- 

 mon in inter- tropical climates. 



Genus 24.— BUCCINUM. 



Animal a Limax; shell univalve, spiral, gibbous; aperture 

 ovate, terminating in a short canal, leaning to the right, with 

 a retuse beak or projection; pillar-lip expanded. 



The Buccina are di\dded by Linnaius into nine idmilies : *inflated, 

 rounded, thin, sub-diaphanous, and brittle ; **mth a short, exserted, 

 reflected beak, lip imai-med outwardly ; ***lip aculeated on the out- 

 side of the posterior part ; in other respects resembling the last divi- 

 E 2 



