A treatise on malacology; or, Shells and shell fish . rnal, some internal,shells, thin or strong, horny orcalcareous, coloured or hyaline;in all these, however, the ovi-form or bulla-shape is uniformlypreserved. The annexed cutfrom Guildings drawings of aspecies allied to B. aperta, willshow how nearly the animal isrelated to the AplysiancB, whileit gives a correct idea of thegeneral character of such typesas have their shell the genus Doridium f of Mecken, the shell almostdisappears ; according to M. Rang ^, the two lateral lobesof the animal are so much developed that they can b
A treatise on malacology; or, Shells and shell fish . rnal, some internal,shells, thin or strong, horny orcalcareous, coloured or hyaline;in all these, however, the ovi-form or bulla-shape is uniformlypreserved. The annexed cutfrom Guildings drawings of aspecies allied to B. aperta, willshow how nearly the animal isrelated to the AplysiancB, whileit gives a correct idea of thegeneral character of such typesas have their shell the genus Doridium f of Mecken, the shell almostdisappears ; according to M. Rang ^, the two lateral lobesof the animal are so much developed that they can beused as fins. Many of the BiiUinee have the gizzardcomposed of bonv pieces; the tentacula assume the ap-pearance of large, fleshy, angulated processes, underwhich are very minute sessile eyes. * See Riippells admirable figure of jVo/arcAM5Mc/w/c/ws, Atlas, i. pi. 2. f Akera Cuv. t Manuel de LHist. Nat. des MoHusques, p. 146. The reader will finda great deal of original and valuable information in this unpretending butexcellent little 252 SHELLS AND SHELL-FISH. PART I. {9,36.) The two next types are Gasteropteron andPleiirohranclms. The first is a most interesting form,since it connects the tribe with the Cephalopoda. Cu-vier, however, with his usual infelicity (wherever na-tural affinities are concerned), simply remarks, that it appears to be an Akera, the margin of whose foot isdeveloped into broad wings for swimming, which it per-forms on its back. It has no shell or stony armature tothe stomach; a slight fold of the skin is the only ves-tige of a branchial operculum that is visible. * A muchbetter account, however, is given by M. Rang f, who ob-serves, that this highly interesting animal was firstmade known by M. Delia Chiaje, the learned anatomistof Naples, who considers it so clearly a Fteropoda, thathe has named it Clio Amati. (237-) The last genus, or rather sub-family, is thePLEUROBRANCHiNiE, distinguished from all others bytheir broad, flattened, and o
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Keywords: ., bookcentury1800, bookdecade1840, booksubjectmollusks, bookyear184
