^EXPLANATION OP PLATE XXXIII. 



Stutchburia compressa, Morris, sp. 

 Fig. 1. Internal cast of conjoined valves showing the hinge line 



Pleurophorus gregarius, Eth. fil. 

 ,, 2. Internal cast of a right valve. 



„ 3. Internal cast of the anterior end of the conjoined valves, showino- 

 the impressions of the cardinal teeth. " 



„ 4. Internal cast of a left valve, with the impressions of the lateral 

 teeth. 



„ 5. Similar to Fig. 3. 



» Mytilops ? ravensfieldensis, Eth, fil. 



„ 6. Internal cast of a left valve. 

 „ 7. Anterior end showing a cardinal fold, x 3- 



