EXPLANATION OF PLATE 9. 



Fig. 4. — Area trilineata Conr. Lateral view. Natural size. 



Fig. 4a. — Area trilineata Conr. Anterior view. Natural size. 



Fig. 4b. — Area trilineata (Jour. Hinge. Natural size. 



Fig. 4c. — Area trilineata Conr. Detail of beading mi tlie ribs. X2. 



Fig. 5. — Area montereyana, n. sp. Lateral view. Natural size. 



Fig. 5a. — Area montereyana, n. sp. Hinge ami inner side of left valve 

 Natural size. 



Fig. 56. — Area montereyana, n. sp. Lateral view of valve shown in fig. 5a 

 Natural size. 



