141 



anterior end. The number of ribs, also, is variable in both; Meek says 

 there are from sixteen to twenty-five in P. subelongata, and D'Orbigny 

 figures two extreme forms of P. Royana, one of which has ten ribs and 

 a half, and the other twenty-nine. The Gabriola Island specimens of P. 

 Hoyana have the beaks placed at a considerable distance from the anterior 

 end, and the length of their shells is not, proportionately, so great as is 

 that of the type of P. mbelongata. In the latter respect they approach 

 very near to P. Brewerii, Gabb, which appears to be only a short variety 

 of P. Roijana. 



HOMOMTA CONCENTRICA, GrABB. 



Panopxa concentrica, Gabb. — Pal. Cal , Vol. I., p. 148, pi. 22, fig. 119. 

 Homomya concentrica, Gabb — Id., Vol. II., p.p. 179 and 236. 



Sucia Islands, in Division A ; J.Richardson, 1874. Two specimena: 

 the largest and most perfect four inches and a-half in length, three inches 

 in height, and two inches and two lines in thickness through the closed 

 valves. The test is marked by coarse, irregular, concentric plications 

 and more or less fine striae of growth, but it can scai'cely be said to be 

 I'ibbed. 



(GONIOMYA BOREALIS, MeKK. 



Pholadomya [Ooniomya) borealis, Meek. — Trans. Alb. Inst., Vol. IV., (1857) p. 41. 

 Goniomya borealis, Meek. — Bui. Geol. & Geogr. Surv. of Terr., Vol. II., 



No. 4, p. 362, pi. 2, fig. 2, 



Nanaimo, Yancouver Island. Meek. Not in any of Mr. Eichardson's 

 collections.) 



Cymbophora Ashburnerii, Gabb. 



Plate 17, figure 8. 



Mactra Ashburnerii, Gabb .—Pal. Cal., Vol. I., p. 153, pi. 22, fig. 127. fiibbed 



variety only. 

 CymbopfiTa A^hburneriij Gabb.— Id., Vol. II., p. 181, pi. 29. fig. 69. 



Middle Shales, Division D, of the north-west side of Hornby Island ; 

 Lower Shales, Division B, at Gabriola Island ; Blunden Point, V. I., 

 Protection and Sucia Islands, in Division A. J. Richardson, 1871-75. 



The hinge teeth are not exposed in any of the sj)ecimens from the 

 above mentioned localities, but the sculpture of the exterior of the shell 

 is very different to that of any other species of Mactra from the Cretaceous 

 rocks of North America, and accords perfectly with Mr. Gabb's descrip- 

 tion of the ribbed variety of C. Ashburnerii. The central area of the 

 valves is ornamented with large, prominent, rounded and rather regular, 



