155 



not undulating, concentric striae, which become coarser and much more 

 rib-like on the posterior area. Hinge teeth and muscular impressions 

 unknown. 



Length, ten lines and a quarter ; height, nine lines. 



Sucia Islands, in Division A, two right valves ; J. Richardson, 1875. 



This shell may be a variety of LcBvicardium annulatum, Gabb,* but it 

 is more distinctly triangular, and its concentric strife do dot appear to be 

 undulating or marked by "small dots, composed of circular or elliptical 

 impressed lines arranged in radiating series," as they are said to be in 

 that species. 



Protocardium scitulum, Meek. (Sp.) 



Cardium scitulum, Meek. —Trans. Albany Inst., 1857, Vol. IV., 



p. 40. 

 Protocardia scitula, Meek. — Bal. Geol. and Geogr. Surv. of Terr., 



Vol. II., No. 4, p. 360, pi. 3, figs. 4 



and 4a. 

 ?= Leptocardia subquadrata, Et. & Sh. (Sp.)— See Meek's Rep. on the Iny. Tert. and 



Cret. Fossils of the U. Miss. Co., p. 



175, pi. 29, fig. 8, a, b, c, d, and e. 

 ?= Leptocardia rara, Ev. & Sh. (Sp.) —Idem, p. 176, pi. 17, figs. 1, a, b and c. 



" Koomooks, Yancouver Island ; Cretaceous." Meek. Blunden Point, 

 V. I., two miles and a quarter and two miles and a half up the Nanaimo 

 Eiver, also at the Sucia Islands, in Division A; J. Richardson, 1871-75. 



Mr. Meek has not failed to notice the strong resemblances that 

 undoubtedly exist between the present species and the Cardium 

 suhquadratum and G. rarum of Evans & Shumard, from the Fort Pierre 

 Group of Dakota. The only difference between Mr. Richardson's 

 specimens of P. scitulum and the two Dakota shells that seems to be con- 

 stant, is that the ribs on the posterior area of the former are distinct and 

 strongly marked, while the corresponding costas of the latter are either 

 obscure, or nearly if not entirely obsolete. When the thin and polished 

 outer layer of the test is exfoliated, which sometimes happens, the 

 central areu of the valves of P. scitulum appears to be concentrically 

 ribbed, and specimens in this condition are very much like young 

 individuals of the C. altum of Forbes. t 



» PalEeontologT of California, vol. I., p. in, pi. 23, fig. 1.52 ; and Vol. ri , p. 18", pi. 30, fig. 81. 

 t Quarterly Journal of the Geological Society of London, Second Series, Vol. VII., 1846, 

 p. 145, pi. 16, fig. 13. 



