UNIVALVE SHELLS. 



51 



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

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

 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 

 Avithout 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 

 families: *apertiu-e or opening entire; **somewhat cylindrical and 

 emarginate ; ***obovate, effuse, and emarginate ; ****fusiforni ; 

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



Valuta 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 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 divided by Linnaeus into nine lamilies: *inflated, 

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

 reflected beak, lip luiaiined outwardly ; ***lip aculcated on the out- 

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



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