EXPLANATION OP PLATE XXXL 



Stutchburia costata, Morris, sp. 

 Pig. 1. Internal cast of a left valve. 



Stutchburia compressa, Morris, sp. 

 „ 2. Internal cast of a left valve. A = crest representing: the 

 hgaiuental (H) pit ia froat of the umbo. 



Stutchburia obliqua, Eth. fil. 

 „ 3. Internal cast of a right valve. 



