486 CRETACEOUS PALEONTOLOGY. 



Genus SPONDYLUS 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. A., 



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 (Monog. 



U. S. G. S., vol. 9), p. 57, pi. 9, figs. 11-12, pi. 10, 



figs. 1-2. 



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

 , P- 12. 



Description* "Shell rather above medium size when fully 

 grown, and generally ovate in form, 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 to> have been only very 

 moderately convex at the apical portions, and to 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.) 



