. Annual report. New York State Museum; Science; Science. 484 NEW YORK STATE MUSEUM pact form, due to its small length (mostly but 6-7 mm) and relatively great width (2 mm when obliquely compressed), the close arrangement of its thecae (14 in 10 mm) and the length of the horizontal, rigid spines ( mm). From the rigidity and the direction of the spines a reference to Glossograptus whitfieldi would appear reasonable, and the Cincinnati specimens have indeed been referred to that species by Ulrich in 1880. The Maquoketa specimens, however, exhibit the peculiar, very narrow or very broad aspe
. Annual report. New York State Museum; Science; Science. 484 NEW YORK STATE MUSEUM pact form, due to its small length (mostly but 6-7 mm) and relatively great width (2 mm when obliquely compressed), the close arrangement of its thecae (14 in 10 mm) and the length of the horizontal, rigid spines ( mm). From the rigidity and the direction of the spines a reference to Glossograptus whitfieldi would appear reasonable, and the Cincinnati specimens have indeed been referred to that species by Ulrich in 1880. The Maquoketa specimens, however, exhibit the peculiar, very narrow or very broad aspects —• according to the face exhibited — of the rhabdosome and the spatulate appendages of the spines characteristic of Lasiograptus [see fig. 465], and show thereby that we have before us a late dwarfed mutation of L. bimucro- natus. The small size, relatively great width, rigidity and length of the spines 464 465" v ^ and probably also the scarcity of the forms Fig. 464-65 Lasiograptus bimucronatus 11 1 ?• t\ ; timid,is nov. Fig. 464 Specimen from utica are all characters pointing to the same shale at Flat creek, Mohawk, N. Y. Fig. 465 specimens from Granger, Minn. x5 phylogerontic condition of this mutation. The Cincinnati specimens are less-shortened than the others and have still more widely arranged thecae (8-9 in 10 mm) ; they would appear to represent a somewhat less reduced mutation than the others. Position and localities. I have before me material of this mutation from the higher Utica shales at Flat creek near Mohawk village, N. Y. (in association with Climacogr. putillus); from the Utica shale at Holland Patent (with Climacogr. typical is and Leptobolus in sign is); from the true Utica shale at Cincinnati [Ulrich collection] and from the Maquoketa shale (Diplograptus bed Sardeson) at Granger, Minn. [Sardeson collection]. ADDENDA Note on Dawsonia The history of this genus of somewhat doubtful standing and the description of two species from the
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