. Annual report. New York State Museum; Science; Science. 156 NEW YORK STATE MUSEUM By tabulating the differentials of these four species we shall in- dicate the features in which D. dolbeli is unlike the rest. pleuroptyx stemmatus anchiops dolbeli Cephalon Short Longer Short Short Occipital ring No spine No spine Spine No spine Confluent papillae on cheeks Conspicuous Inconspicuous Inconspicuous Inconspicuous Suture line on cheek Flush Flush Depressed Flush Pygidium Lateral ribs 11-13 9-10 8-9 8-9 Axial ribs i3-(i5) 9-(n) 9-0 4) 10-O3) Ribs Deeply grooved, rounded Not grooved, rounded Not gro
. Annual report. New York State Museum; Science; Science. 156 NEW YORK STATE MUSEUM By tabulating the differentials of these four species we shall in- dicate the features in which D. dolbeli is unlike the rest. pleuroptyx stemmatus anchiops dolbeli Cephalon Short Longer Short Short Occipital ring No spine No spine Spine No spine Confluent papillae on cheeks Conspicuous Inconspicuous Inconspicuous Inconspicuous Suture line on cheek Flush Flush Depressed Flush Pygidium Lateral ribs 11-13 9-10 8-9 8-9 Axial ribs i3-(i5) 9-(n) 9-0 4) 10-O3) Ribs Deeply grooved, rounded Not grooved, rounded Not grooved, rounded Faintly grooved, rounded Caudal spine Short, acute, elevated ax- ially Broad, obtuse, not elevated axially Slender, extend- ed, upturned, not elevated axially Broad, some- what extend- ed, upturned, blunt, and not elevated axially Sharing its principal structures with the other three and sep- arated from them by differentials which are of the same quality as those distinguishing other members of the series, D, dolbeli represents a notably early Devonic type of structure. Dimensions. Cephalon: large examples attain an axial length of 40 mm and a width of 75 mm. Pygidium: an average example has a length of 40 mm and a width of 60 mm. Lower Devonic. Grande Greve and Shiphead, P. O. Dalmanites lowi no v. A very distinct type of structure is presented by a few pygidia which are of considerable size, relativelv quite short, broad at the. Dalmanites lowi top, with pleural ribs 10 or 11 in number, the last three of which are simple and faint but all the rest very strongly duplicate through- out their entire extent becoming obsolete at or just within the margin. The axis is broad and the dorsal furrows rapidly approx-. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original New York State Museum. Albany : Unive
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectscience, bookyear1902
