Eigs. 86. /. ineonstans, elongate form, Upper Chalk; left valve. 87-89. I. hal- 

 ticus Bolim, Upper Chalk : 87, right valve of slightly convex form ; 

 88 & 89, left valve and anterior view of fullj -grown convex foi-m. 

 90. /. lingua Groldf., Upper Chalk : right valve. 91. /. lobahis Groldf., 

 Actinocamax-quadratus Zone. 92. /. cardiss,oides Groldf., A.-q. Zone ; 

 left valve. All @ half of the natural size, 

 Q. J. G. S. No. 269. c 



