PROTOCARDTA. 199 



? 1878. Protocardium Hillanum, 0. Fraas. Aus dem Orient. II Geol. Beobacht. 



am Libanon, p. 70. 

 1882. Cardium (Protocardium) Hillanum, P. tie Loriol. Gault de Cosne, p. 



69, pi. viii, fig. 17. 

 1884. Protocardium Hillanum, J. F. Whiteaves. Mesoz. Foss. (Geol. Surv. 



Canada), vol. i, p. 228, 

 pi. xxx, fig. 5. 

 ? Cardium (Protocardia) Hillanum, C. E. Hamlin. Mem. Mus. Comp. 



Zool., vol. x, No. 3, p. 50. 

 1893. Protocardium Hillanum, R. Michael. Zeitschr, d.deutsch.geol.Gesellsch., 



vol. xlv, p. 232. 



1 897. A. Fritsch. Stud, im G-ebiete der bobm. Kreide- 



format., vi, Chlomek. Schiclit., 

 p. 52. 

 R. Leonhard. Kreidef. in Oberschles. (Pal- 

 seontographica, vol. xliv), p. 28. 



1898. A. Fritsch. Stud, im Gebiete der bijbni. Ivreide- 



format., iii, Iserschicht., p. 98. 



1901. Protocardia Hillana, F. Sturm. Jalirb. d. k. preussisch. geol. Landes- 



anst. fiir 1900, vol. xxi, p. 79. 



1902. A. Quaas. Kreidebild. in der libysch. Wiiste 



(Palfeontographica, vol. xxx, 2), 

 p. 218, pi. xxiv, fig. 18. 

 1904. R. Fortau. Bull. Instit. Egyptien, ser. 4, no. 4, 



p. 331. 

 var. umkwelanensis, R. Etheridge, jun. Second 

 Rep. Geol. Surv. Natal and 

 Zululand, p. 79, pi. i, fig. 16. 

 1906. var., H. Woods. Cret. Fauna of Pondoland (Ann. 



S. African Mus., vol. iv), p. 307, 

 pi. xxxvii, fig. 6. 



Descrijitiov, — Shell convex, with flattened posterior slope, nearly equilateral ; 

 outline more or less sub-quadrate, rounded, sometimes nearly oval ; usually a 

 little higher than long, but rarely with the height and length equal Anterior 

 margin either fairly convex and forming a rounded angle with the antero-dorsal 

 margin, or very convex and passing almost gradually into the antero-dorsal 

 margin. Anterior margin passes gradually into the ventral margin, which may be 

 considerably convex, but is usually only slightly convex, with its posterior part 

 nearly straight and forming a more or less well-marked angle with the posterior 

 margin. The latter is truncated, slightly convex, and forms an obtuse angle with 

 the postero-dorsal margin. Umbones of moderate size. 



Ornamentation consists (except on the posterior part of the shell) of numerous, 

 very regular, rounded, concentric ribs separated by narrow furrows ; these ribs 

 become smaller or nearly obsolete near the antero-dorsal margin. On the posterior 



