UNIVALVE SHELLS. 51 



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

 irivers, and ditches. The marine species are found a few inches imdei 

 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 contract itself whoUy mtliin 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 sheUs into five distinct 

 famihes : *aperture or opening entii-e ; **somewhat cylindrical and 

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

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



Voluta episcopalis — The Episcopal Voluta. Plate 

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

 smooth, margin of the volutions entire; lip denticulated; 

 columella with four plaits. Five inches long. Inhabits 

 the Indian ocean Variously spotted with orange. 



Voluta 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 pUlar-lip or columella. 



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

 mon in intei'-troi^ical 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 Bucciua are divided by Linnaeus into nine lamilies : *inflated, 

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

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

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



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