143 



by their peculiar and apparentl}' constant sculpture, which is not very 

 tve'il represented in the figure on plate seventeen.* The sm-face is marked 

 by from one to three faint, shallow grooves, or aiTests of growth, which 

 extend from margin to margin. When there are three of these grooves, 

 which there generally are in adult shells, the first and second are wide 

 apart, and the second and third comparatively close together. In 

 addition to these mai-kingt>, the central area of the valves, though polished 

 and apparently smooth, or nearly to, to the naked eye, when examined 

 with a lens is seen to be covered with regularly arranged, crowded and 

 minute concentric striae. On the lunule and escutcheon these strise are 

 developed into prominent, rather distant, rib-like ridges, which are 

 plainly visible without the aid of a magnifying glass. So far as the 

 surface markings are concerned no intermediate gradations have as yet 

 been observed between these finely striated and coarsely ribbed shells. 



M. Warrenana appears to be closely allied to the M. angulata of 

 Sowerby,f but the description of the latter shell is too short and insuffi- 

 cient to allow of an accurate comparison between the two species. 



TeLLINA (PER0N.a;0DERMA ?) MaTHEWSONI, GaBB. 

 Tellina Mathetosoni, Gabb.— Pal. Cal., Vol. I., p. 158, pi. 23, fig. 136. 



Nanaimo Eiver, V. I., two miles and a half up, in Division A; J. 

 Richardson, 1875. A somewhat imperfect cast with portions of the 

 test preserved. Mr. Gabb says that the beaks of this species are central, 

 but in his figure of the shell they are represented as slightly behind the 

 middle. In the specimen from Vancouver Island their position is 

 distinctly behind the middle. 



Tellina ((Ene?) Sp. Undt. 

 Plate 17, figure 10. 



Shell small, much compressed, transversel}' and narrowly sub-elliptical, 

 about twice as loBg as bigh, test extremely thin. Extremities narrowly 

 rounded, the posterior being rather narrower than the anterior ; anterior 

 side produced, elongated ; posterior side short. A small posterior area 

 is very obscurely indicated by an abrupt and obliquely convex com- 

 pression of the valves behind and above a line which might be drawn from 

 the rear of the beaks to the base, but the umbonal ridge is not very 



• As this figure lias not proved satisfactory, two additional illustratioiit of the species have 

 been given on plate 19. 



t Transactions ol the Geological Society of London, Series 11., Vol. iv., (1836) p, 341, pL 16, 

 fl^. 9. 



