597 



Janira mortoni d'Orbigny, 1850, Prod. Paleont. Strat, vol. ii, p. 253. 

 Pecten quadricostatus var. Roemer, 1852, Kreide. von Texas, p. 64, pi. viii, 



figs. 4a-4c. 

 Pecten quadricostatus Shumard, 1854, Marcy, Expl. Red River, Louisiana, 



p. 178, pi. ii, figs. 2a, 2b; pi. iii, fig. 6. 



Neithea mortoni Gabb, 1862, Proc. Acad. Nat. Sci., Phila. for 1861, p. 365. 

 Neithea mortoni Meek, 1864, Check List Inv. Fossils N. A., Cret. and Jur., 



p. 7. 



Neithea mortoni Conrad, 1868, Cook's Geol. of New Jersey, p. 725. 

 Pecten quadricostatus Credner, 1870, Zeitsch. deutsch. geol. Gesell., Bd. 



xxii, p. 232. 

 Vola quinquecostata Stoliczka, 1871, Mem. Geol. Survey India, Palaeont. In- 



dica. Cret. Faunas of Southern India, vol. iii, p. 437, pi. xxxi, figs. 1-6; 



pi. xxxviii, figs. 4-9. 

 Neithea quinquecostata Whitfield, 1885, Mon. U. S. Geol. Survey, vol. ix, p. 



56, pi. viii, figs. 12-14. 

 Neithea quinquecostata Weller, 1907, Geol. Survey of New Jersey, Pal., vol. 



iv, p. 481, pi. Ii, figs. 7-12. 

 Vola quinquecostata Bose, 1910, Bol. Inst. Geol. Mexico, p. 99, pi. xv, figs. 



19, 20. 



Description. " Subtriangular, rather oblique, front semicircular, 

 toothed ; convex valves gibbous, ribbed, principal costa six, with four lesser 

 ones between each ; surface finely transversely striated. Upper valve flat- 

 toothed. The obliquity of this shell is slight, the length not much greater 

 than the width ; the lines of growth frequently being deep and crossed by 

 the ribs give the shell a fringed or furbellowed aspect ; the flat valve has 

 diverging striae and notches corresponding in number with the costs upon 

 the hollow valve. The whole surface is covered with minute transverse 

 stria?, which in the chalk specimens are often nearly obliterated. Figs. 

 4 and 5 are from the Sussex chalk near Lewes, by favor of G. A. Mantell, 

 Esq. ; they very much accord with those of the green sand from Wiltshire, 

 figured below, but appear to be longer, and to have the transverse striae of 

 growth very remarkable. The shell represented at fig. 5 is a curiosity, 

 showing the inner side of the flat valve, which is slightly convex within. 

 I gathered the small shell, fig. 6, at Chute farm, it is a young deep under- 

 valve, with the transverse striae of growth neatly arching between the larger 

 six coste. Figs. 7 and 8 show the upper and under valves of different 

 specimens, they are from the green sand at Chute, and are chiefly siliceous ; 

 for the use of one I am indebted to Thomas Meade, Esq. Such are said 



