486 CRETACEOUS PALEONTOLOGY, 



Genus Spondy^us Linneus. 

 Spondylus gregalis (Morton). 



Plate LIIL, Figs. 1-3. 



1833. Plagiostoma gregalis Mort., Am'. Jour. Sci. ist ser. vol, 



23, p. 292, pi. 5, fig. 6. \ 



1834. Plagiostoma gregale Mort., Synop. Org. Rem. Cret.Gr. 



U. S., p. 60, pi. 5, fig. 6. \ 



1861. Spondylus gregalis Gabb, Synop. Moll. Cret. Form. p. 



227 (171). 

 1864. Spondylus gregalis Meek, Check List Inv. Foss. N. \., 



Oret. and Jur., p. 7. . 



1868. Spondylus gregalis Con., Cook's Geol. N. J., p. 724. 

 1886. Spondylus gregalis Whitf. Pal. N. J., vol. i (Mono. 



U. S. G. S., vol. 9), p. 57, pi. 9, figs. 11-12, pi. I; 



figs. 1-2. \ 



1905. Spondylus gregale Johns., Proc. Acad. Nat. Sci. Phi 



(1905), P- 12. 



Description. — "Shell rather above medium size when full) 

 grown, and generally ovate in fo'rm, with the lower or attached 

 valve somewhat the deepest. Cardinal area large, but short, 

 much extended and flattened on the surface ; transversely striated \ 

 and with a narrow linear groove through the middle; teeth \ 

 strong. Surface of the lower valve strongly lamellose on the ' 

 free portions; the attachment apparently being only small and 

 near the apex ; between the lamella, which are elevated, the sur- \ 

 face shows indistinct radiations, which on the interior are quite 

 distinctly marked and flexuose, and are comparatively fine. The 

 upper valve not observed, except as shown on casts of the in- 

 terior. In this condition it is shown toi have been only very 

 moderately convex at the apical portions, and toi have been flat- 

 tened or but very slightly convex toward the front, with the 

 surface radiated as in the case of the lower valve, but whether 

 the exterior has been lamellose or only simply radiated I have 

 not been able to ascertain." (Whitfield.) 



