JR. S. Lull — Fossil Dolphin from California. 219 



being nearly parallel as in Delphinus, the two bones are sepa- 

 rated by a wide lenticular space, the curved line of the radius 

 being particularly noticeable. In the ulna the olecranon is 

 better developed but simple in outline. 



Hand. — The carpus is essentially alike in both genera, but 

 here again the fossil is the more primitive in that the magnum 

 is represented by a well-defined lenticular bone lying at the 

 proximal end of metacarpal III ; whereas in the specimen of 

 Delphinus used for comparison, it is reduced to a tiny nodule 

 closely adpressed against the unciform and visible only from 

 the inner aspect of the wrist. Its position, however, is exactly 

 the same in each form. In the fossil the bones of the anterior 

 side of the carpus have been displaced, but their identity 

 seems fairly certain. 



The metacarpals show much the same proportions in each 

 genus, but the preserved phalanges are relatively longer and 

 more slender in the fossil, no separate phalangeal epiphyses being- 

 discernible. The digital reduction has gone further in the 

 modern type, as evidenced by the proximal phalanx of digit 

 IV, which is a much better developed bone in the fossil. 



Measurements of the pectoral limb. 



Delphinavus Delphinus 



Cat. No. 10040 Cat. No. 265 



Scapula, height .. 105 mm 104 mm 



" breadth 146 160 



Humerus, length 60 60 



" proximal breadth 37 49 



" ant. -post, diameter, distal end. 31*5 38*5 



" transverse " mid shaft. 19'5 24 



Radius, length 67'3 84 



" diameter, proximal end 25 28 - 5 



" '-' distal end 33 37'5 



Ulna, length. 71-5 72 



" diameter, proximal end 26*5 30 



" " distal end 26 27 



Metacarpal II T, length 20 32 



" " breadth of shaft 11 14 



Digit III, 1st phalanx, length 19-5* 21*5f 



" 2d " " 11-5 17 



" " 3d " " 08 13 



Length of digit, inc. metacarpals, estimated 80 100 



" " entire limb, inc. scapula, " 320 360 



SumnMry. 



The specimen under consideration is clearly a dolphin allied 

 to Delphinus and hence of the family Delphinidse. It com- 



* No epiphyses nor articular cartilages indicated, but bones are spaced. 

 f Including epiphyses, bones in contact. 



