414 



GASTEROPODA. 



[ORM. PAL. 



complanata, Vanuxem, 1842, Geo. Rep. | 

 N. Y., p. 36, and Pal. N. Y., vol. 1, p. 1 

 11, Calciferous Gr. 



complanata var. nana, Meek, 1870, Hayden's , 

 U. S. Geo. Sur. Terr., p. 295, and Geo. j 

 4th Parallel, vol. 4, p. 17, Calciferous Gr. \ 

 disjuncta, Billings, 1865, Pal. Foss., vol.1, 



p. 344, Calciferous Gr. 

 levata, Vanuxem, 1842, Geo. Rep. N. Y., 

 p. 36, Calciferous Gr. 



nerine, Bill- 

 ings, 1865, ! 

 Pal. Foss., ' 

 vol. 1, p. 245, ! 

 Quebec Gr. 

 ottawensis, 



Billings, 1860, i 

 FIG. 689.-Ophileta nerine. Can. Nat. and 



Geol., vol. 5, p. 167, Trenton Gr. 

 owenana, Meek & Worthen, 1868, Geo. 



Sur. 111., vol. 3, p. 313, Galena Gr. 

 primordialis, Winchell, 1864, (Straparol- 

 lus primordialis,) Am. Jour. Sci. and 

 Arts, 2d ser., vol. 37, p. 228, and Geo. 

 Wis., vol. 4, p. 173, Potsdam Gr. 

 profunda, Billings, 1865, Pal. Foss., vol. 1, 



p. 188, Quebec Gr. 



uninangulata, Hall, 1847, (Euomphalus 

 uniangulatus,) Pal. N. Y., vol. 1, p. 9, 

 Calcifer. Gr. 



ORMATHICHNUS, S. A. Miller, 1880, Jour. Cin. 

 Soc. Nat. Hist., vol. 2, p. 222. [Ety. 

 ormathos. string of beads ; ichnos, track.] 

 Supposed to be the trail of a Gastero- j 

 pod, and consisting of a continuous < 

 beaded track or trail. Type O. monili- ! 

 formis. 



moniliformis, S. A. Miller, 1880, 

 Jour. Cin. Soc. Nat. Hist., vol. 

 2, p. 222, TJtica Slate Gr. 

 ORTHONEMA, Meek & Worthen, 1861, 

 Proc. Acad. Nat. Sci., Phil., p. 

 146. [Ety. orthos, straight; 

 nema, thread.] elongate, many 

 whorled, ornamented with re- 

 volving carinse, crossed by nearly 

 straight lines of growth ; body 

 whorl angular, not much en- 

 larged or produced below ; aper- 

 ture angular above, slightly 

 effuse below ; peristome incom- 

 plete ; outer lip simple, nearly 

 straight ; axis imperforate. 

 Type 0. salteri. 



carbonarium,Worthen, 1884, Bull. 

 No. 2, 111. St. Mus. 

 Nat. Hist., p. 7, and 

 Geo. Sur. 111., vol. 

 8, p. 145, Coal Meas. 

 conicum, Meek & Worthen, 

 1866, Proc. Acad. Nat. Sci. 

 Phil., p. 270, and Geo. Sur. 

 111., vol. 5, p. 590, Coal Meas. 

 newberryi, Meek, 1871, Proc. 

 Acad. Nat. Sci. Phil., p. 81, 

 and Ohio Pal., vol. 1, p. 

 217, Up. Held. Gr. 



salteri, Meek & Worthen, 1860, (Eunema (?) 

 salteri,) Proc. Acad. Nat. Sci. Phil., p. 



464, and Geo. Sur. 111., vol. 2, p. 381, 

 Low. Coal Meas. 



subtjeniatum, Geinitz, 1866, (Murchisonia 

 subtseniata,) Garb, und Dyas in Neb., 

 p. 12, and Pal. E. Neb., p. 228, Coal Meas. 



Orthonychia, Hall, 1843, syn. for Platyceras. 



ORTHOSTOMA, Conrad, 1838, Ann. Rep. N. Y., 

 p. 119. [Ety. orthos, straight; stoma, 

 mouth.] Shell spiral, spire plain, con- 

 vex, terminal volution, ending in a 

 straight tube. Type 0. commune. 



FIG. 690. 



O r t h onema 



newberryi. 



FIG. 691. Orthostoma commune. 



commune, Conrad, 1838, Ann. Rep. N. Y., 

 p. 119, figured in 1841, Ann. Rep. pi. 

 2, fig. 16, Birdseye Gr. 



AL^ACM^A, Hall & Whitfield, 1873, 23d 

 Rep. N. Y. Mus. Nat. Hist., p. 242. 

 [Ety. palaios, ancient ; Acmsea, an exist- 

 ing genus of shells.] Conical, more or 

 less elevated ; apex subcentral, erect or 

 slightly curved ; peristome entire, not 

 sinuate ; surface marked concentrically. 

 Type P. typica. 



FIG. 692. Palaeotrochus kearneyi. 



irvingi, Whitfield, 1878, Ann. Rep. Geo. 

 Sur. Wis., p. 51, and Geo. Wis., vol. 4, 

 p. 173, Potsdam Gr. 



,ica, Hall & Whitfield, 1873, 23d Rep. 



\ Y. Mus. Nat. Hist., p. 242, Pots- 

 dam Gr. 



PAL^EOTROCHUS, Hall, 1879, Pal. N. Y., vol. 

 5, pt. 2, p. 133. [Etv, palaios, ancient ; 



Trochus, a genus.] Oonical, trochiform ; 

 spire elevated ; volutions moderately 



tyg. 



