400 R. Bullen Neicfon — Egyptian Cretaceous Shells. 



with concentric, lamellose, irregular growth-lines crossed by 

 numerous obscure plications ; upper valve concave, truncated at the 

 summit, operculiform, and of similar sculpture to the opposing 

 valve, but without radial ornamentation. 



Dimensions. 



Both valves in contact — Height 82 mm. 



Length 101 ,, 



Diameter ... ... ... 45 ,, 



The shells referred to this species have very robust, thick tests, 

 and vary somewhat in size. From 0. hiauriculata and other allied 

 species, they differ in the possession of radial costse and the usually 

 scaly appearance of the lower valve. On account of the presence 

 of a posterior expansion, this species is placed in the genus 

 Gryphcea, a view first adopted by Stoliczka.^ 



Eemarks. — All the specimens are in a fine state of preservation, 

 and what little matrix accompanies them is a yellowish-white 

 limestone. 



Horizon. — Turonian. 



DisTKiBUTioN. — Algeria ; Tunis ; Golea, westward of Abu Eoasch, 

 Egypt ; west of Gizeh Pyramids : Coll. Greol. Surv. Egypt (No. 68, 

 Box No. 30c). 



Genus PROTOCARDIA, Beyrich, 1845. 

 Zeitschrift Malakozoologie (Hanover), 1846, p. 17. 

 Type. — Cardium Hillanum, J. Sowerby. 



Protooardia biseriata, Conrad. PL XV, Fig. 11. 

 Cardium biseriatum, Conrad, " Desc. Fossils Syria " : Official Eeport 



United States Exped. Dead Sea, etc. (W. F. Lynch), 



1852, p. 216, pi. vi, figs. 38, 39 {non fig. 40). 

 Cardium (Protocardia) Hillanum, Hamlin, " Syrian Molluscan 



Fossils": Mem. Mus. Comp. Zool. Harvard College, 



voL X (1884), p. 50. 

 Protocardia Eillana, var. tijpica. Blanckenhorn : " Beitrage Geologie 



Syriens," 1890, p. 89. 

 Description. — Shell " rotundate-cordate ; ventricose, subequi- 

 lateral ; posterior side rather longer than the anterior ; the margin 

 subtruncated and nearly direct ; summits prominent, acutely 

 rounded ; basal margin profoundly rounded anteriorly, obliquely 

 truncated in rear; surface of the valves marked with concentric 

 lines as far as the umbonal slope ; posterior subraargin with about 

 fifteen slender minutely echinated radii ; posterior margin crenulated 

 within. This abundant species resembles Cardium peregrinosum, 

 Orbigny, and C. Hillanum, Sowerby, but is proportionally more 

 elongated, and the sulci are much larger. The largest specimen 

 measures 2^ inches in length." — Conrad. 



^ It should he stated here that G. Costei is only quoted by Stoliczka in 

 a general list of Cretaceous species, and not as occurring in India, where, apparently, 

 it has never been identified. 



