'14:-2 IXTKODUCTION TO COXCHOLOGY. 



parent. The little glass shell which pertains to the Lir/ia- 

 cina may be described as hvaline, spiral, obliquely discoid, 

 with a membranaceous lamellar keel, having a lai'ge and 

 entire aperture, and being slightly iullated on each side. 

 The genus Cre-seis displays a conically-formed shell, of a 

 pale rose-colour ; Cuvieria, a thin, white, cylindrical, globular' 

 or hemispherical one, of which the posterior end is rounded, 

 obtuse, and truncated, the anterior depressed and open, 

 with a transverse and slightly oblique aperture ; Cijiahidia, 

 a larger and more intricately constructed shell, partially 

 chanaced into a kind of o'elatinoQS crystalline inteo-ument of 

 an oblong, slipper-Kke shape, truncated posteriorly, open 

 anteriorly, with a nearly lateral aperture. 



Such are the elegant and singularly varied boats in 

 which these interesting moUusks sail at eventide, on the 

 calm still surface of the deep, when day has faded into twi- 

 light, and stars begin to twinkle in the immensity of space. 

 Imagine a lleet of such meek creatures, resting quietly on 

 the scarcely heaving billows, while as yet the setting sun 

 tlu-ows a golden gleam athwart them, and each small boat 

 reflects the parting radiance. Think of them, when mid- 

 night settles on the deep, alone, unfearing, although im- 

 mensitv is over them and beneath them, and the heavens at 



