142 True On South American Delphinidce. 



end of maxilla, do not accord with that genus. Indeed the 

 character last mentioned is not present in any genus of the Del 

 phinidce with which I am acquainted. If the drawings of the 

 skull are correct in this particular, the species probably repre 

 sents a genus not hitherto known. Further study of the type- 

 specimen can alone resolve the problem. 



"Tursio platyrrhinus Philippi" (1896, p. 16, pi. 4, fig. 1; pi. 5, fig. 1; 



pi. 6, fig. 1?). 



I am of the opinion that this species should be assigned to 

 the genus Cephalorhynchus, and that in spite of the differences 

 in the skull shown by the figures, it is probably the same as the 

 albiventris Philippi, which I consider identical with C. eutropia 

 (Gray). Dr. Philippi remarks of it: 



The nasal bones are very peculiar, are flat and do not ex 

 tend out at all; they do not touch the intermaxillse as in the 

 foregoing species (albiventris) but only the maxillae, and each 

 exhibits a large oblique cavity, which occupies the middle of 

 the bone, The beak is a little narrower than in the preceding 

 species, and I should have referred the two skulls of T. platyr 

 rhinus to that species, if I did not believe that the different 

 form of the nasals is a distinguishing character of the greatest 

 importance.* 



In view of the great amount of individual variation in the 

 form of the nasals in all species of the Delphinidce, it does not 

 seem probable that this character alone is sufficient for the sep 

 aration of species. 



It will be noted that the shape of the beak in T. platyrrhinus 

 as given on pi. 4, fig. 1, is very different from that in albiven 

 tris, but by examining the contour of the same skull shown in 

 pi. 5, fig. 1, it becomes obvious that the outline in the former 

 case is incorrect. I cannot help suspecting also that figure 3, 

 plate 6, is intended to represent platyrrhinus, and figure 1 of 

 the same plate, albiventris. 



The species mentioned or described by Dr. Philippi and their 

 probable identity as indicated above are as follows: 



*0p. cit., p. 16. 



