PLATE 3 . 



Page. 

 Fig. 1. Inoceramos umbonatus 44 



1, a. An inner view of the type-specimen, consisting of an internal cast of the uuibonal region, 

 with some portions of the coarsely fibrous shell attached, showing the great thick- 

 ness of the latter. 



1, b. An anterior side view of same, without the attached portion of the shell (natural size). 



1, c. An interior view of a large internal cast of the left valve, reduced to one-half the nat- 



ural diameter. 



FIG. 2. INOCEKAMUS TJNDABUNDUS 00 



2. a. Side view of type-specimen, consisting of an internal cast of the left valve. [The hinge- 



margin of this specimen is not exactly placed horizontally as the figure stands on 

 the plate, but ranges a little obliquely forward and downward.] 

 2, b. An anterior view of same (both natural size). 



