. Annual report of the regents of the university of the state of New York on the condition of the State Cabinet of Natural History and the historical and antiquarian collection annexed thereto. Fig. 9, 10 & 11 are front, profile and cardinal views of a full-grown individual which has becomevery ventricose. Its wide geographical distribution and considerable vertical range make it aninteresting species. In its external features it presents no variation or diflference ofimportance from other Rhynchonellee; but the interior structure of specimensrecently examined shows some peculiarities, which,
. Annual report of the regents of the university of the state of New York on the condition of the State Cabinet of Natural History and the historical and antiquarian collection annexed thereto. Fig. 9, 10 & 11 are front, profile and cardinal views of a full-grown individual which has becomevery ventricose. Its wide geographical distribution and considerable vertical range make it aninteresting species. In its external features it presents no variation or diflference ofimportance from other Rhynchonellee; but the interior structure of specimensrecently examined shows some peculiarities, which, if constant, are incompatiblewith the characters of that genus as determined from existing and some well-marked fossil species. This species, like some others of the genus, becomes extremely gibbous or ven-tricose with age, and the apex of the ventral valve is closely incurved over thebeak of the opposite valve. Nor is this all; for the beak is perforate, and in manyspecimens we are able to discover a distinct foramen in the substance of the shell:indeed sometimes this foramen is above or exterior to the apex of the beak, butit is rarely possible to distinguish the continuity of the
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Keywords: ., bookcentury1800, bookdecade1850, booksubjectscience, bookyear1853
