EXPLANATION OF THE PLATES. 



Note. — The figures following the authority for the specific name denote the actual length in milli. 

 meters of the longest diameter of the figure, whether that be the height or the breadth, except where 

 otherwise stated. 



PLATE I. 



FKt. 1. Corbula Krebaiana C. B. Adams; 6.1. 

 1 a. " 



1 I). " " 



2. liasterotia quadrata Hinds ; 10.0 ; left valve. 



2 a. Same, hinge seen from above. 



2 b. " " " " below. 



3. Corbula Knoxiana C. B. Adams; 12.7; front. 



3 a. " " back of left valve. 

 3 b. " 



3 c. " " 



4. Corbula disparilis D'Orbigny ; 9.0. 



4 a. " " 



4 b. " " 



5. Corbula Dietziana C B. Adams; 10.7. ' 



5 a. " 



5 b. " " 



6. Corbula Kjoeriana C. B. Adams; 12.0 



6 a. " " 

 ()b. " " 



7. Corbula cymella Dall ; 13.5. 



7 a. " 



All the above, except figures 2 a, 2 b, and 4 a, 4 b, are drawn by W. H. Dall with 

 the camera Iticida from typical specimens of the describer in the museum at Am- 

 herst, 



The following plates (I-XL) are from the Report on the MoUusca of the Blake Expedition, parts I 

 and II, drawn by J. C. McConncU (except where otherwise stated) from the specimens. For the use 

 of these plates we are indebted to Prof. Alex. Agassiz. 



PLATE II. 



Fig. 1 a, 1 b. Verticordia (Euciroa) elegantissima Dall ; 13.25. 



2, 2 a. Halomjmplia claviculata Dall ;• 12.0. 



3 a, 3 b. Cardiomya 2)erro8trata Dd]\ ; 8.0. 



4 a, 4 b. Verticordia {Haliris) Fischeriana Dall ; 10.0. 



5 a-5 c. Corbula Siviftiana C. B. Adams, from type ; 10.4. 



6 a-6 d. Corbula Chittyana C. B. Adams, from type ; 8.5. 



7, 7 a-c. Corbula Barrattiana C. B. Adams, from types; 8.9. 



177 



24781— Bull. 37 12 



