A treatise on malacology; or, Shells and shell fish . still moreclose analysis of the whole. The result of this, in re-gard to the theory of variation, was communicated to theZoological Society in 1835.* This theory is now foundto pervade the whole class of Testacea ; while, in ourSystematic Arrangement, will be found all the well-known and clearly described species, distributed undertheir several minor groups. The MitrincE, in comparisonto the volutes, with two or three exceptions, are muchsmaller shells, chiefly distinguished by the smaller sizeof the foot, as in Mitra episcopalis {fig. 13.)
A treatise on malacology; or, Shells and shell fish . still moreclose analysis of the whole. The result of this, in re-gard to the theory of variation, was communicated to theZoological Society in 1835.* This theory is now foundto pervade the whole class of Testacea ; while, in ourSystematic Arrangement, will be found all the well-known and clearly described species, distributed undertheir several minor groups. The MitrincE, in comparisonto the volutes, with two or three exceptions, are muchsmaller shells, chiefly distinguished by the smaller sizeof the foot, as in Mitra episcopalis {fig. 13.), where theproboscis is excessively long; and by the greater lengthof their spire, the tip of which is never papillary,f The * Proceedings of the Zool. Society, part iii. p. 197 + Except in two or three species of Mitreola, which blend into Harjmla. 128 SHELLS AND SHELL-FISH. PART 1. upper plaits of the pillar, in almost all, are larger thanthe lower; and the general form of the shell is equallyor unequally fusiform. It is almost impossible to esti-. mate the number of species, as new ones are constantlycoming to light; but there probably exists already, in ourcabinets, about two hundred and fifty, of which morethan forty were brought home by Mr. Cummin fromthe western coast of Tropical America. We suspect,from these data, that, in a few years, the increase ofknown species will come near to 300, leaving out thosethat belong to the three aberrant genera—Mitre/la,Conabhelijr, and Mitreola. Nearly all these are excludedfrom the European seas ; and, what is still more extra-ordinary, not more than half a dozen can be called com-mon shells. This scarcity of mitres certainly does notoriginate from the difficulty of gaining access to theirhaunts; for, although some are known to live at greatdepths*, yet both MM. Stuchbury and Cummin informus that they generally found these shell-fish in shallowwater, near coral reefs. Hence we conjecture that theirchief metropolis must be the great
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Keywords: ., bookcentury1800, bookdecade1840, booksubjectmollusks, bookyear184
