54 



of the interior of that valve. It is much flattened exteriorly, and its 

 surface is nearly smooth, possibly as a result of weathering prior to 

 fossilization. Its beak is erect, and its "cardinal area " and " deltidium " 

 are not flattened obliquely backward and receding, as those of the 

 T. Lindstrmmi from Gotland are. Its interior does not present any 

 additional characters to those of Davidson and King's restoration of the 

 pedicle valve of T. grandis on Plate 13, fig. 2c, of their paper on the 

 Trimerellidse (op. cit.), but the platform vaults are apparently a little 

 longer in proportion to the entire length of the valve. 



Teimeeella acuminata, Billings. 



Trimerdla acuminata, HiWingB 1862. Geol. Siirv. Canada, Pal. Foss., 



vol. I., p. 167 and p. 168, fig. 151. 

 " " Da-sidson & King. .1874. Quart. Journ. Geol. Soo. Lond., 



vol. XXX., p. 146, pi. 15, figs. 4-7, and 

 pi. 16, figs. 1 and 2. 



Nicholson 1875. Rep. Pal. Prov. Ont. , p. 68, fig. 36. 



Hall 1892. Pal. N. York, vol. VIII., pt. 1, 



pi. 4 B, fig. 6. 



This species has been collected at the same localities as Trimerella 

 grandis, and almost invariably in the same condition, viz., as casts of the 

 interior of the shell. A large but very imperfect pedicle valve of a 

 specimen of T. acuminata, with part of the test remaining, though in els 

 very bad state of preservation, was, however, collected at Hespeler in 

 1867 by Mr. T. C. Weston. It has most of the beak broken off, as well 

 as a large portion of one side of the valve, and shows little more than that 

 the surface of the test is marked by concentric lines of growth, at irregular 

 intervals. 



Teimeeella Ohioensis, Meek. 



Plate 10, figs. 1 and la. 



Trimerella Ohioensis, Meek 1871. Am. Journ. So. cfe Arts, Ser. 3, vol. 



I., p. 315. 



" Dall 1871. Am. Joiirn. Conch., vol. VIL, pt. 



2, p. 83. 



Meek 1873, Rep. Geol. Surv. Ohio, vol. I, pt. 



2, p. 183, fig. u,, and pi. 16, figs. 1, a-c. 

 " " Davidson & King. .1874. Quart. Journ. Geol. Soc. Lond., 



vol. XXX., p. 153, pis. 16, figs. 3-7, and 

 19, figs. 1 and 2. 



Hall 1892. Pal. N. York, vol. VIIL, pt. 1, p. 



35, pi. 4A, figs. 3-9. 



"Guelph limestone, Canada? one valve, E. Billings." Dall. The 

 writer has either not seen or has failed to recognize the specimen referred 



