56 BULLETIN NO. 30, UNITED STATES NATIONAL MUSEUM. 



Page. 



Mollusea 335 



Brachiopoda 335 



Utrophomena, Raflneaquo, 1820 ? 335 



8. unicostata, n. s., M. &. W., 1868, pL iv, figs. 11 a, 6 335-337 



LamellWranchiata 337 



Ambonychia. ITall, J 847 337 



SubReuus Meijaptera, M. & W., 1866 337 



Mcfjapfera casei,M. &. W., 1866, pi. iv, figs. 9 a, 6 337-338 



X>oto6ra, McCoy, 1844 339 



D. uterlingensin, M. .Sc W., 1866, pi. iv, figs. 10 a, b,c 339-340 



Gasteropoda 340 



Cyrtolites, Conrad, 1&38 340 



0.imbricatus,-a.s.,M. &. W., 1868, pL iv, fig. 12 340-341 



Pteropoda 341 



TentacuUtes, Scblotheiui, 1820 341 



T. tenuistriatus,'iS. iW., 1865, pi. iv, figs. 7 a, 6 341-342 



T. oswegoensig.yi. & "W., 1865, pi. iv, fig. 6 a 342-343 



T. sterlingmsis.M.. & "W., 1865, pi. iv, fig. 8 343 



TTppek Silurian Species. 



fossils of the niagara group. 



Protozoa 344 



Spongice 344 



Astylospongia, Roemer 344 



A. ?? christiani, n. s., M. & W., 1868, pi. v, figs. 3a,b,c 344-345 



Pasceolue, Billings, 1853 345 



P. I dactylUjides, Owen, sp. , 184 4, pi. v, figs. 2a,b,c _ 345-346 



JRadiata 347 



JEchinodermata 347 



. Saccocrinus, Hall, 1852 347 



S. christyi, B.ani sp., 1863, pL v, fig. 1 347-349 



Mollusea 349 



Brachiopoda 349 



Hemipronites, Pander, 1830 349 



H. subplanus,Co-aTa.A'>. .sp., 1842, pi. vi, figs 6 a,b 349-351 



Obolus, Eichwald, 1829 351 



O. [TrimereUa^ cojirftdi. Hall, 1868, pi. v, figs. 7 a, & 351-352 



Centronella, Billings, 1859 352 



C. bilKngsiana, u. s., M. &. W., 1868, , p. 352, figs, a-e, and pi. vi, figs. 5 a^-c 352-353 



Meristella, Hall, 1860 354 



Meristella ? sp., pi. vi, figs. 4 o, & 354 



Lamellibranchiata 354 



Pterinea, Goldfuss, 1832 354 



P. thebesensis, n. s. , M. &, W., 1868, page 354, fig. — , and pi. vi, fig. 3 354-355 



Ambonychia, Hall, 1847 356 



A . acutiroxtris, Hall ? 1H65, pi. v, figs. 8 a, b, and 9 c 356-357 



Amphicoelia, Hall, 1864 357-358 



A.7U'glecta,'M.cCheiwy, 18G1, pi. v, figs. 9 n, & (note) 358-359 



Gasteropoda 359 



Pleurotomaria^ Defrancf, 1824 359 



P. casii. n. s., M. & W., 1868, pi. v, flg. 5 359-360 



P. cyclonevioides, -a. B., M. & W., 1868, pi. v, fig. 4 360-361 



Sitbtdites (Conrad), Emmons, 1842 361-362 



S. (Polyphemopsis) brevis, "Winchell & Marcy, 1865, pi. v, fig. 6 352-303 



Articulata 363 



Crustacea 363 



Dalmanites, Auct 363 



D. dance, M. &W., 1865, pi. vi, fig. 1 a-/ 363-367 



FOSSILS OF THE LOWER HKLDEHBERG GROUP. 



Radiata 368 



Zoophyta 368 



(Sf(rta<oj9ora, Hall, 1852 368-369 



S. missouriensis, n. 8.,M. &. "W., 1868, pi. vii, fig. 4 369-370 



Echinodermata '. 370 



