A treatise on malacology; or, Shells and shell fish . on ^i. ar-cularia. (59.) The typical distinction of the Nassje lies ina very thick deposition of enamel which encircles theaperture, and not only spreads far beyond the inner lip,but forms a vitreous mass all over the under part ofthe body-whorl. The only other genus of predaceousTestacea having a shell thus constructed, is Cassis, anda few tritons, w^hich are probably its , there are many Kassce which have thispeculiarity but slightly developed, and others in whichit is not at all apparent; in all, however, ther
A treatise on malacology; or, Shells and shell fish . on ^i. ar-cularia. (59.) The typical distinction of the Nassje lies ina very thick deposition of enamel which encircles theaperture, and not only spreads far beyond the inner lip,but forms a vitreous mass all over the under part ofthe body-whorl. The only other genus of predaceousTestacea having a shell thus constructed, is Cassis, anda few tritons, w^hich are probably its , there are many Kassce which have thispeculiarity but slightly developed, and others in whichit is not at all apparent; in all, however, there is a pro-minent internal ridge at the base of the pillar, and asmall transverse tooth on the upper part of the innerlip. These shells are all of a small size, and aboundin the shallow waters of Southern Europe and the the unpublished researches of Guilding*, is ahighly finished drawing of a species from St. Vincents{), which throws an important light on the animal: * Now in the possession of his widow. CHAP. III. Tin: NASSIXiE. 69. from this, it does not appear to have a probosciformmouth; but the anterior part of the foot is prolonged intoa subulate point on each side, and the hinder jmrt termi-nates in two littletail-like this has muchof the character ofour genus Leiodo-nius *, figured byQuoy and Gaimard;and, although boththey and their shells are too dissimilar to be placedin the same group, they may be considered analogous. (60.) The broad, spreading, and dilated inner lip ofCassis prepares us at once for the sub-family of Nassin^e,which is entered by the genus Cassidaria of shells differ from all those we have just left, byhaving the basal canal considerably more lengthened,and only slightly turned backv/ards, without reposing onthe shell itself: they are of an intermediate size be-tween the largest Nassce and the smaller helmets ; andthus the gradation even of size is preserved. The typi-cal genus Nassa then succeeds : the s
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Keywords: ., bookcentury1800, bookdecade1840, booksubjectmollusks, bookyear184
