AND THE WEST COASTS OF THE UNITED STATES. 



135 



Table III. 



CORRELATION BETWEEN POSTERIOR AND ANTERIOR PARTIAL LENGTHS OP RIGHT VALVES (TAMPA). 



4 =27.138mm.; <7 o = 2.205. 

 = 2.199. 



Table IV. 



CORRELATION BETWEEN POSTERIOR AND ANTERIOR PARTIAL LENGTHS OP RIGHT VALVES (SAN DIEGO). 



= 580. A a 

 A, 



= 19.113; 

 = 22.095; 



, = 2.716. 

 , = 3.436. 



EXPLANATION OF PLATE IX. 



Photograph by the three-color process of the original objects. 

 Fig. 1. Three right (lower) and three left (upper) valves of Pectens from the Tampa (T., above) and from the 



San Diego (S. D., below) lots for comparison of color and markings. The six valves to the left are lower 



valves; the six to the right are upper valves. 

 Fig. 2. Comparison of right valves with the greatest and smallest number of rays from Tampa (T.) and San 



Diego (S. D.) 



