. Annual report. New York State Museum; Science; Science. SOME NEW DEVONIC FOSSILS 263 allied in this respect to T. perforata Hall than to any other though it differs substantially even from that. This shell has the following characters: The ventral sinus is not bounded by the median primary pair of plications but by the primary pair just out- side the median, the latter in later growth making a pair on the slopes of the wall of the sinus. Likewise the median rib on the dorsal valve, while constituting the crest of the median fold is accompanied by a pair of ribs of primary age which modify th
. Annual report. New York State Museum; Science; Science. SOME NEW DEVONIC FOSSILS 263 allied in this respect to T. perforata Hall than to any other though it differs substantially even from that. This shell has the following characters: The ventral sinus is not bounded by the median primary pair of plications but by the primary pair just out- side the median, the latter in later growth making a pair on the slopes of the wall of the sinus. Likewise the median rib on the dorsal valve, while constituting the crest of the median fold is accompanied by a pair of ribs of primary age which modify the slopes of the fold. At the beak and continuing for one third the length of the shell without modification the number of plications on the ventral valve is 12, on the dorsal valve II. From this point outward the ribs irregularly dichotomize into two or sometimes three, fold and sinus being affected like the rest of the surface. The shell is transverse with straight hinge and without cardinal areas. The ventral beak is abruptly perforate and the shell sub- stance punctate. Lower Devonic. Dalhousie, N. B. Chonetes impensus nov. A large shell having the aspect of Leptostr op h i a oris- k a n i a but with coarser striae. The single specimen observed of this species is a ventral valve, regularly convex, with very fine sub-. Chonetes impensus equal striae for about one half its length followed beyond a distinct growth line by much coarser striae. Hinge margin cornute, Hight 21 mm, length 28 mm. Specifically unlike any form known to the writer. Lower Devonic. Moosehead lake, 7 miles north of Kineo, Me. Chonetes nectus nov. A small coarse ribbed species, transversely elongate in form and having 14 to 16 striae, each of the larger of which is divided at variable distances from the middle to the margin of the valve. It is but slightly convex compared with C. hudsonicus Clarke. Please note that these images are extracted from scanned page images that may have been digitally enhanced for
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectscience, bookyear1902
