291 



East end of Maud Island, Dr. G. M. Dawson, 1878 : the " perfect right 

 valve" referred to P. Ilillanum on page 228, and figured on Plate 30, 

 fig. 5, of this volume. A few small but well preserved casts of the interior 

 of shells which are probably referable to this species, were collected on 

 the south side of Alliford Bay by Dr. Dawson in 1S78 and by Dr. New- 

 combe in 1895. 



Judging by Sowerby's original description and figure of Cardium, 

 HiUanuin, from the Greensand of Blackdown, the ]\Iaud Island specimen 

 would seem to be a very much smaller shell, with a somewhat difierent 

 marginal outline. As figured in the " Mineral Conchology", C. Hillanum 

 is an inch and three-quarters in its maximum length, but the Maud 

 Island right valve may not be that of an adult shell. 



Meekia sella, Gabb. 



Meekia sella, (xabb. 1864. Geol. Surv. Calif., Palaeont., vol. i, p. 191, pi. 25, fig. 179. 

 Periploma cnspidatwni, Whiteaves. 1884. This volume, part 3, p. 220, pi. 29, figs. 4 and 

 4, a-h. 



Bear Skin Bay, Skidegate Inlet, C. F. Newcombe, 1895 : one speci- 

 men. 



The types of Periploma cuspidatum from Maud Island are badly pre- 

 served casts of the interior of small specimens, with the valves spread out, 

 which show nothing more than the marginal outline of the shell and a 

 short groove in each valve, curving downward and a little outward on one 

 side of the beak. The largest of these casts is twenty-eight (not " twenty ") 

 millimetres in its maximum length, and twenty-four and a half in height. 

 From their general appearance it was supposed that the shorter and 

 " abruptly cuspidate " side was analogous to the beaked posterior side of 

 Cusindaria or Pandora, and that the umbonal groove corresponded to 

 the impression of the obliquely transverse, posterior internal rib seen in 

 so many of the Cretaceous Anatinidfe and especially in Corimya. It 

 was, however, fully recognized that the marginal outlines of these speci- 

 mens is singularly like that of the Meekia sella, as figured by Gabb. 



Quite recently, by the courtesy of Professor Pilsbry, the types oi Meekia 

 sella, from Martinez, in the Museum of the Academy of Natural Sciences 

 of Philadelphia, have been lent to the writer for examination and com- 

 parison. They consist of seventeen different valves, of all sizes, some of 

 which are perfect and well preserved, with the whole of the test remain- 

 ing. The largest, which is noc the one figured by Gabb, is a perfect left 

 valve, fifty millimetres in length, by forty-four in height. These speci- 

 mens show clearly that the test of M. sella is porcellanous and compara- 

 tively thick, not subnacreous and thin as in Periploma proper : also that 



