22 INVEBTEBRATE ANIMALS. 



Group 63. -Family CARDIID^ and allies. xa/sSia, the 

 heart. Cockles. Estimated numher of species : recent, 

 162 ; British, 9 ; fossil, 300. From the Silurian 

 upwards. 



U Cardium, Hemicardia, Bucardia, dc, 

 Adacna and Monodachna are generic forms from 

 the Caspian. 



Group 64.— Family CYRENIDiE and allies. Cyrene, the 

 daughter of a river. The olive-green epidermis indi- 

 cates a fresh-water habit. Estimated number of species : 

 recent, 255 ; British, 12 ; fossil, 195. Tertiary. 



^ Illustrations of the genera in the families Glau- 

 conomyidce, Cyrenidce, Cyrenoididce. 



Family VENERID^. 

 Group 65. — Genus TAPES (Megerle) and allies, tapes, 

 tapestry. Estimated number of species : recent, 257 ; 

 British, 8 ; fossil, 60. Tertiary. 



H Dosinia = Artemis, Tapes, Circe, dementia, Rupel- 

 laria, d:c. Sunetta, fine series of species. 

 Group 66.— Genus VENUS and aUies. Estimated number 

 of species : recent, 238 ; British, 6 ; fossil, 160 ; from 

 the Oolite upwards. 



IT Venus, Callista, Chione, dtc. 



Chione Kellettii, from the Dennison collection. 



Family TELLINID^. 



Group 67.— Sub-family DONACINiE, and allies. Wedge- 

 . shells. Estimated number of species : recent, 227 ; 

 British, 10; fossil, 60. Tertiary. 



11 Donax, Mesodesma, Semele, Ervilia, dc. 

 Note. — The beautiful interior of Galatea, from 

 African rivers. 



