[WHITRAVES] VANCOUVER CRETACEOUS FOSSILS 128 
CYTHEREA ARATA, Gabb. 
Meretrix arata, Gabb. 1864. Geol. Surv. Calif., Palæont., vol. i., p. 166, pl. 30, 
fig. 250. 
SE *  Gabb:. "1869070; vol: 11.5 p. 240: 
Cytherea (Callista) laciniata, Whiteaves. 1879. Geol. Surv. Canada, Mesoz. Foss., 
vol. i., pt. 2, p. 148, pl. 17, figs. 13 and 18a, and pl. 
19, figs. 4 and 4a, but perhaps not Cytherea (Cal. 
lista) laciniata, Stoliczka, 1871. 
The specimens referred to Cytherea (Callista) laciniata, Stoliczka, in 
the “ Mesozoic Fossils” (op. cit., p. 148) have recently been found to be 
exactly similar to a specimen from the Chico group of Tehama County, 
California, which Mr. Stanton has identified with Meretrix arata, Gabb, 
and kindly loaned to the writer. The original description of the sculp- 
ture of M. arata is rather misleading. According to Mr. Gabb, its sur- 
face is “ornamented by regular, concentric, acute impressed lines,” 
whereas, in the writer’s judgment, it would be much more correct to say 
by small, concentric, rounded ribs, with very narrow furrows between 
them. 
CYPRIMERIA LENS, Whiteaves. 
Cyprimeria lens, Whiteaves. 1879. Geol. Surv. Canada, Mesoz. Foss., vol. i., pt. 2, 
p. 152, pl. 17, figs. 15 and 15a, but not Meretrix lens, Gabb, 1864, 
which is probably not a Cyprimeria. 
a ‘ White. 1889. Bull. U.S. Geol. Surv., no. 51, p. 42. 
Shell compressed convex, moderately inflated, ovately subcircular in 
marginal outline, and nearly as high as long ; posterior side a little 
longer, and in some specimens rather more narrowly rounded than the 
anterior; basal margin broadly convex; superior border descending 
rapidly and obliquely in front of the beaks, gently convex and slightly 
prominent immediately behind them, thence curving gradually down- 
ward to the posterior end ; beaks placed a little in advance of the mid- 
length, small, depressed, appressed and curved forward. No definite nor 
distinctly-margined lunule, and apparently no well-defined escutcheon. 
Test rather thick, its surface polished and marked with numerous 
very fine and closely disposed concentric striæ, also with four or five dis- 
tant and coarser linear concentric grooves or periodic arrests of growth. 
Hinge with two cardinal teeth and one lateral tooth in the left valve. 
The two cardinal teeth are transverse and divergent, the anterior one 
being thick and excavated in the middle, but not bifid. The lateral 
tooth, which is thin and feebly developed, is partially separated from 
the cardinal fulcrum by a narrow, shallow groove. Anterior muscular 
impression large and subovate ; posterior muscular scar, pallial line and 
hinge dentition of the right valve unknown. 
Northwest side of Hornby Island, J. Richardson, 1872: one left 
valve. Sucia Islands, J. Richardson, 1874; three imperfect right valves 
