. 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. Science. No. 186.] 83 pearance of a false area on the ventral valve, somewhat similar to Atrypa, the margin being thickened and grooved; but this does not appear to be a characteristic or constant feature. The specimens of the interior, which have fallen under my ob- servation, usually preserve only the short crural processes; and it is in one specimen alone, which is partially filled with crystalline m
. 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. Science. No. 186.] 83 pearance of a false area on the ventral valve, somewhat similar to Atrypa, the margin being thickened and grooved; but this does not appear to be a characteristic or constant feature. The specimens of the interior, which have fallen under my ob- servation, usually preserve only the short crural processes; and it is in one specimen alone, which is partially filled with crystalline matter, that distinct cavities can be seen corresponding with what I have described. The crystalline matter was flrst deposited upon these internal organs, which have subsequently almost entirely decomposed, leaving in the cavities fragments of the substance, showing the original form of the crura and appendages. The shells of this form have been described as Terebrattjla, and more recently have been included with Rhtnchonella, from which they differ conspicuously in the great inequality of the valves and the extension of the hinge-line, as well as in their internal structure. The accompa,nying illustrations show all that has been thus far determined relative to the internal structure 0/ this genus. Figures 1, 2 and 4 are from specimens of L. JiahelUtes; and fig. 3 is a nearly perfect specimen of L. Jimhriata. I I. Tig. 1. The interior of the ventral valve, showing the cardinal teeth and the muscular impression. Fig. 2. Interior of the dorsal valve, showing the cardinal process j, the teeth sockets b b, the bases of tlie crura c c, and the short thickened septum which divides the muscular impression. Fig. 3. An enlarged figure of L. fimbriata, showing the usual form, the foramen at the beak, and the fimbriie on the cardinal margin. Fig. 4. The interior as shown in a specimen of L. flabellites, where it has been partial- ly filled with crj'stalline quartz. Tiie decomposition of t
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Keywords: ., bookcentury1800, bookdecade1850, booksubjectscience, bookyear1853
