PLEIOCEJNTE FOSSILS. 



PLATE XV. 



ARCACIDJ]. 



Fig. 1. AECA EUSTICA. Fragment of the only specimen in our possession. The outline is 



correct. Page 39. 

 " 2. AECA LrENOSA. Exterior of left valve, and hinge and teeth of right valve. Page 40. 

 " 3. End view, showing outline of hinge and untbones. 



" 4. AECA IMPEOCEEA. Exterior of left valve, and hinge and teeth of right valve. Page 41. 

 " 5. End view, shewing outline, hinge and umbones. 

 " 6. AECA TEANSVEESA. Exterior of left valve, and hinge and teeth of right valve. 



Page 42. 

 " 7. End view, showing outline of hinge and umbones. 



