50 On the Soulhern Snnpplng-Turtle. 



wltich was referred to the only species then known, Chelydra 

 serf endna, but under the name of var. ocutimstn's*^ tlie 

 snout beinp^ considered as rather more pointed than in the 

 s) eciniens from North America. This difference, however, 

 does not exist, I think, as a constant character. Another 

 great authority, the late Professor Cope, in 1872 f, also referred 

 the South-American Snapper to ClieJydra .s^>-^)?h//««, adding : 

 " I can find no specific difference between shells from Penn- 

 sylvania, Mexico, and Equator." Having now received 

 several s))ecimens, adult and ycung, from North- western 

 Ecuador, through Mr. Rosenberg, I find that the species is 

 certainly diffeient from the North American, which appears 

 to range from Canada to Northern Mexico, and the same as 

 described by Bocourt :j: from quite young specimens obtained 

 in Mexico and Guatemala, under the name of Chelydra Eos- 

 higiionii, a name which should stand in preference to that of 

 acutiro&tn's, the latter not being accompanied by a proper 

 definition. 



The specimens examined by me are a male, a female, and 

 a young from the Rio Durango, N.W. Ecuador, 350 feet, 

 and two young from St. Javier, N.W. Ecuador, 60 feet. 



Some measurements of these are given in the following 

 table, in the order mentioned : — 



1. 2. 3. 4. 5. 



nun. nun. nnu. mm. mm. 



Length of carapace 270 200 5(5 60 (5() 



„ plastron 20.> ir,,5 40 49 50 



Width of plastral bridge 25 20 7 8 8 



Length of lirst vertebral shield ..50 40 9 13 12 



^Vidth „ „ „ . . 58 60 13 17 15 



Length of second „ „ .. t'3 45 10 13 12 



Width „ „ „ •• 6<J 50 15 17 17 



Length of first costal shield 70 60 12 15 15 



Width ., „ „ .... 83 60 15 J7 18 



Length of abdominal shield 26 20 7 8 8 



Width „ „ .... 58 50 13 16 15 



From these measurements it will be seen that the plastral 

 bridge is broader and the vertebral shields narrower than 

 in 6'. serpeniina, comparing, of course, specimens of the same 

 size. Besides, C. Rossignonii differs in having two pairs 

 of small mental barbels instead of one. 



1 have already pointed out that § Ch. Rossignonii appears 



* Mon. Berl. Acad. 1862, p. 627. 



t Pr.c. Ac. Pbilad. 1^<72, p. 23. 



: Miss. Sc. Mex., Kept. p. 18, pi. v. fig. 2 (1870). 



§ Cat. Chelon. p. 23. 



