PLATE 80. 



Fig. 1. 707. I. Megalomus canadensis. (Pag. 343.) 



1 a. The .-intorior half of a large individual, preserving the shell. The line continued, marks the outline of 



the entire valve. 

 1 b. View of the anterior extremity, showing the unibones, and a part of the dorsal margin. 

 1 c. The dorsal side of the same specimen. 

 1 </. A fragment of the left valve of another specimen. 

 1 e. Dorsal view of a cast of this species. 



