IfUMERICAL ESTIMATE. 



135 



Eecent. Fossil. 

 Nuclcohranch lata. 



Firolidae 33 1 



Atlantidse 22 159 



55 



Pteeopoda. 



Hyaleidse 52 



Liraacinidae 19 



Clionidce 14 



Beachiopoda. 



Terebratulidre 67 



Spiriferidge — 



Rhynchonellidse 4 



Orthidae — 



Productidse — 



Craniadae 5 



Discinidse 10 



Lingulidee 16 



102 



160 



95 



95 



340 

 380 

 422 

 328 

 146 

 37 

 90 



1,842 



Recent. FossU. 



CONCHIFEEA. 



Ostreidse 426 1,362 



Aviculidae 94 638 



Mj^ilidffi 217 331 



Arcadse 360 1,142 



Trigoniadse 3 139 



UnionidxB 549 58 



Chamidse 50 62 



Hippuritidee — 103 



Tridacnidse 8 3 



Cardiadge 200 369 



Lucinidse. 178 44fi 



Cycladida 176 144 



Cyprindffi 176 956 



Veneridse 600 329 



MactridjE 147 68 



TeUinidse 560 388 



Solenidae 63 81 



Myacidge 121 334 



Anatinidse 246 400 



GastrochgenidsB 40 35 



Pholadidffi 81 50 



4,295 7,419 



General Summary. 



Recent. Eossil. 



Dibranchiata 204 189 



Tetrabranchiata 6 2,193 



Prosobranchiata 8,465 5,819 



Inoperculated Pulnaonif era 5,404 542 



OperculatedPulmonifera.. 931 46. 



Tectibranchiata 356 263 



Nudibranchiata 318 — 



Eecent. Fossil. 



Nucleobrancliiata 55 



Pteropoda 85 



Bracliiopoda 102 



Conchifera 4,295 



16» 

 95 



1842 

 7,419 



20,502 18,568 



