1883.] 



PROF. FLOWER ON THE DELPHINID/E. 



487 



D. 12, L. 10, C. 22, making a total of .51 vertebrse, very different there- 

 fore from the skeleton of D. {Steno) ■perspicillatus described by Dr. 

 Peters. As remarked in the original description, " the principal dif- 

 ferences between this skeleton and that of all other known Dolphins 

 lie in the vertebral column. The total number of vertebrae is less, 

 tbe individual vertebrje are proportionally longer, and their transverse 

 processes are shorter and broader than in any other species. Next 



Fig. 7. Palate of Sotalia sinensis. 



to it iu these characters stands D. gu'ianensis^ (genus Sotalia, Gray), 

 which has the following vertebral formnla — C. 7, D. 12, L. 14, 

 C. 22 = 55." Among other differential characters it was also 

 pointed out that " the manus is broader at the base than in most 

 Dolphins (e. g. B. delphis and D. tursio) and much resembles in 

 form that of D. guianensis as figured by Prof. Van Beneden. This 

 breadth is caused by the considerable development and position of 

 the two outer digits. The number of ossified elements of each 

 digit (excluding the metacarpals) are — I. 0, II. fi, III. 5, IV. 2, V. 1. 

 Though the manus thus differs in some characters from that of the 

 Common Dolphin, the metacarpal and phalangeal bones are of the 

 usual character, i. e. contracted in the middle of their outer borders, 

 or hour-glass siiaped, thus differing greatly from the form observed 

 in the true Steno (if D. perspicillatus is to be taken as typical of 



' Mum. de TAcad. Eoy. de Belgique, Coll. in 8to, t. xvi. 18G3, p. 33. 



