stanton.] LIMN.EID.E, NAUTILID2E. 163 



LIMN^ID^l. 

 Genus PHYSA Draparnaud. 



Physa sp. % 



P ] UJsa f White, 1879, Ann. Kept. U. S. Geol. Sur. Terr, for 1877, p. 307, PL 7, 



Fig. 13a ; 1883, 3d Ann. Eept. U. S. Geol. Sur., p. 444, PI. 4, Fig. 5. 



A single specimen of Physa, too imperfect for specific description, 

 was found by Dr. 0. A. White in the " second ridge " at Coalville, Utah, 

 where it was associated with many marine species of the Colorado 

 formation. It is the only example of the genus that has been foand in 

 that formation. 



CEPHALOPODA. 



NAUTILOIDEA. 



NAUTILID^E. 

 Genus NAUTILUS Breynius. 

 Nautilus elegans Sowerby. 



PI. xxxv, Fig. 1. 



Nautilus elegans Sowerby, 1816, Min. Conch., vol. n, p. 33, PI. 116 ; Sharpe, 1853, Monog. 



Chalk Cephal. of England, p. 12, PL 3, and. many other European authors. 

 Nautilus elegans var. nebrascensis Meek and Hay den, 1862, Proc. Acad. Nat. Sci., Phila., 

 p. 25. 

 Nautilus clegansMeek, 1876, U. S. Geol. Sur. Terr., Vol. ix, p. 499, PL 8, Figs. 2, a, I), c. 

 Compare Nautilus texanus Shumard, 1860, Trans. St. Louis Acad. Sci., vol. I, p. 590. 



Meet's description is as follows: 



u Shell subglobose, broadly rounded over the periphery and on each 

 side of the umbilicus, which is closed in young and medium-sized speci- 

 mens, but becomes a little open in the adults; volutions increasing rap- 

 idly in size, considerably wider transversely than in the dorso- ventral 

 direction, all of those within entirely embraced and hidden by the last 

 one; aperture transversely reniform-sublunate, being profoundly sinu- 

 ous on the inner side for the reception of the inner turns; margins of 

 the septa arching forward a little near the umbilicus, slightly waved 

 backward on the sides, then again curving very slightly forward as they 

 approach the periphery, in crossing which they bend again almost im- 

 perceptibly backward; siphuncle placed a little outside of the middle 

 of the septa ; surface of the outer volution ornamented by regular flat- 

 tened, transverse costae (about five times as broad as the narrow, shal- 

 low grooves between) and moderately distinct lines of growth, which, 

 like the costae, in crossing the periphery, arch gracefully and deeply 

 backward, parallel to the deep peripheral sinus of the margin of the 

 lip. 



