. Zoological illustrations, or, Original figures and descriptions of new, rare, or interesting animals, selected chiefly from the classes of ornithology, entomology, and conchology, and arranged according to their apparent affinities . ircle. If the student compares thesecharacters with Trochus Zizyphinus, a common Britishshell, he will immediately perceive the leading differencesbetween the two groups. But it is the calcarions nature of the operculum (as in-dicating an important difference in the organization of theanimal) which constitutes the primary character of Marma-rostoma : the particu
. Zoological illustrations, or, Original figures and descriptions of new, rare, or interesting animals, selected chiefly from the classes of ornithology, entomology, and conchology, and arranged according to their apparent affinities . ircle. If the student compares thesecharacters with Trochus Zizyphinus, a common Britishshell, he will immediately perceive the leading differencesbetween the two groups. But it is the calcarions nature of the operculum (as in-dicating an important difference in the organization of theanimal) which constitutes the primary character of Marma-rostoma : the particular structure of this appendage variesconsiderably in the different species : in some its outersurface is smooth and convex; and in others variouslygranulated. In the present shell it is marked by three orfour deep semicircular grooves ; that nearest the middleis the deepest, and terminates in an umbilicus. In somespecimens, the spines on the principal ridge of the bodywhorl are nearly obsolete; but those which crown the sum-mit appear constant. We are indebted to the Rev. Mr. Buhver, a scientificand arduous Conchologist, for our specimens of this newspecies, purchased by him in a collection sent fromPanama. Marmarostoma PI.
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Keywords: ., bookcentury1800, booksub, booksubjectmollusks, booksubjectzoology
