103 



(ARCA ? EQUILATERALIS, MeEK. 



Area (Cucullxa?) equilateralix^ Meek. — Trans. Alb. lust., 1857, Vol. IV., p. 40. 

 Area? equilateraliSj Meek. —Bui. Geol. and Geogr. Surv. of Terr., Vol.11., 



No. 4, p. 357, pi. 2, figs. 6 and 6a. 



"Nanaimo(?) Yancouvei- Island ; Cj-etaceous.'" Meek. Not obtained at 

 any of the localities visited by Mr. Eiehanison.) 



Nemodon Vancouverensis. Meek. (S]».) 



Plate 19, figures 1 and la. 



Area Vancouverensis, Meek. — Trans. Alb. In.st, Vol. IV., p. 40. 



Area Breweriana, Gabb. —Pal. Cal., Vol. I., p. 193, pi. 25, fig. 181. 



Grammatodon ? Vancouvereims, Meek. — Bui. Geol. and Geogr. Surv\ Terr., Vol. II., No. 



4, p. 356. pi. 3, figs. 5 and 5<i. 



'• Koomooks, Vancouver Island ; CretaeeDUs."' Meek. South-west side 

 of Hornby Island, in Division D ; south-east end and south-west side of 

 Dennian Island, in Divisions C and B ; Sable Eiver and Blunden Point, 

 V. I., in Division A; J. Eichardson, 1871-73. 



This species was described from individuals which \vere ju-obably 

 immature; for the length of the ty])e figured b}' Meek is stated to be 

 0-75 inch, and the height 0-47. The specimens collected by Mr. 

 Richai'dson, which ai-e believed to be referable to .4. Vnncouverensis, show 

 that the shell, when adult, attained to a length of u])wards of three 

 inches, and to a height of about twenty-two lines. The dentition of the 

 hinge is always remarkably constant in its characters, but the outline of 

 the valves varies considerably in different individuals. In some the 

 hinge line and basal margin ai-e nearl}' parallel, the posterior eud is 

 rather squarely truncated, and the two extremities are nearly equal in 

 breadth. This must be regarded as the typical form, it being the one 

 which corresponds most nearl}^ to Meek's description and figures of A. 

 Vancouverensis. In another variety the posterior side is distinctl}' Avider 

 than the anterior; the hinge line and basal mai-gin are not quite parallel, 

 but somewhat divergent, and the cardinal margin ascends graduall}' from 

 the anterior to the posterior end ; the venti-al border rounds up rapidly 

 in a broadly convex curve from the middle of the valves to the termina- 

 tion of the hinge line in front; the posterior end is obliquely truncated 

 above and blunth' pointed below. The fine adult specimen from Blunden 

 Point, represented on plate 19, gives a good idea of the sha])e of this 

 variety, which, howeve.-. is connected with the more typical form of the 

 species by several intermediate gradations. 



