160 



right valve and two in the left, whereas in 0. Geinlt-Aina there are 

 three teeth in each valve. 



ASTARTE CONRADIANA, GaBB. 

 Plate 18, figures 5 and 5a. 

 Astarie Conradiana, Gabb.— Pal. Cal., Vol. I., p. 178, pi. 24, fig. 161. 



Sucia Islands, in Division A. ; J. Richardson, 1874 and 1875. Abundant, 

 perfect and beautifully preserved. 



The beaks of the Californian types of A. Conradinna are described as 

 " overhanging the anterior end," but those of the specimens collected by 

 Mr. Eichardson are invariably placed at some distance from the front 

 margin and are never quite terminal. Most of the hinge dentition is 

 exhibited in two fragments, one of which is figured. There are two 

 teeth in the left valve, one cardinal and the other lateral, and between 

 the two there is a deep, oblique, triangular pit. The cardinal tooth is 

 prominent, ti'ansverse and placed close to the lunular margin of the 

 valve and parallel with it. The lateral tooth is elevated on the anterior 

 half of the lower margin of the hinge plate only, and is grooved longitu- 

 dinally above. In the opposite valve there is an oblique, triangular 

 tooth immediately under the beak, but the posterior portion of the 

 hinge of the only right valve in which the characters of the interior are 

 exposed is too much broken to show whether there was a lateral tooth or 

 not, or wh5kt it was like if there was. 



AsTARTE Conradiana, yar. Tuscana, CIabb. 



Plate 18, figure 6. 



Astarte Tuscana, Gabb. —Pal. Cal., Vol. I., p. 129, pi. 30, fig. 257. 



Astarte cardinioiies, Whiteaves. — Geol. Surv. Canada. Eep. Progr. 1873-74, p. 2G7, pi. 



of foss., fig. 3. 

 Astarte Vancouverensis, Whiteaves. — Idem, p. ;i67, pi. of foss., fig. 4. 



North-west Bay, V. I., and at the Sucia Islands, in Division A; J 

 Eichardson, 1872 and 1874. 



Mr. Richardson's specimens show clearly that Astir'e Tuscana is only 

 a variety of J.. Co?(ra(?iVma. Tie posterior end of the present shell is 

 doubtless narrower, more elongated, and more comprei-sed laterally than 

 it is [in A. Conradiana pi'opei-, but in a large and fine series of both 

 forms, from the Sucia Islands, the anterior end of each is precisely simi- 

 lar, as may be seen by a comparison of figures 5 and 6 on Plate 18. The 

 types of Astarte cardinioides prove to be only large and badly preserved 

 individuals of .4. T'^.sca/^a, with their ribs worn flat under the matrix, 



