OF THE CHINESE WHITE DOLPHIN. 159 



The following are the principal dimensions of the pectoral limb : — 



inches. 



Scapula. — Height 6-4 



Breadth , . . 9-0 



Length of acromion 2-6 



Greatest depth of acromion 2'1 



Length of coracoid process 1*4 



Length from head of humerus to tip of fin 13 - 



Greatest breadth of fin 5 - 



Length of humerus 2 - 9 



Length of radius 3-4 



Length of ulna 3T 



Breadth of radius at distal extremity 2 - 



Breadth of ulna at distal extremity 1*3 



The principal differences between this skeleton and that of all other known Dolphins 

 lie in the vertebral column. The total number of vertebra? is less, the individual vertebra? 

 are proportionally longer, and their transverse processes are shorter and broader than in 

 any other species. Next to it in these characters stands I), guianensis (genus Sotalia, 

 Gray), which has the following vertebral formula:— C. 7, D. 12, L. 14, C. 22 = 55 ; then 

 D. tursio, which has C. 7, D. 13, L. 17, C. 25=62. D. clelphis, with C. 7, D. 13, L. 24, 

 C. 31=75, is at the other extreme, being only exceeded in number of vertebra?, and 

 length and narrowness of the processes by the Lagenorhynchi. 



If the osteological characters possessed by this specimen be found to exist in other 

 Dolphins with narrow, compressed beaks and long mandibular symphyses, Steno will be 

 established as a natural group of generic value. 



DESCRIPTION OF THE PLATES. 



PLATE XVII. 



Fig. 1. Side view of the skeleton of Delphinus sinensis, presented by Mr. Swinhoe to the 



Museum of the Royal College of Surgeons : one-fourth of the natural size. 

 Fig. 2. Dorsal view of the same skeleton, without the pectoral limbs. 



vol. vii. — part u. Jan. 1870. z 



