244 PKOCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



liead, G times in total leiigtli of body. Width of pectoral a little less 

 than tbau two-t birds its length; the posterior lobe coutaiiied 3% times 

 in its anterior lobe. 



Claspers, in specimen described, not reaching nearly to edge of ven- 

 tral. 



Teeth of upper jaw broadly triangular, nearly erect, uot notched on 

 the outer margin, the edges distinctly and rather coarsely serrate. 

 Lower teeth narrowly triangular, with broad base, the edges finely 

 serrate. Teeth in the young scarcely narrower than in the adult. 



The specimen here described was uot preserved, it having spoiled 

 before the arrival of alcohol. 



Among the described species of this geinis Carcliarinmplafyodon (Poey) 

 (^=ohtusus Poey) seems to be most nearly related to the species ex- 

 amined by us. The pectoral in C. platyodon is larger, the teeth some- 

 what dift'ei-ent, and the second dorsal is said to be "assez grande," 

 whereas in C. coeruleus the latter fin is very small. (J. fronto, lately de- 

 scribed by us from Mazatlan, is also verj^ similar, but has a much larger 

 second dorsal. 



Another species, similar, but with longer snout, has been described by 

 Dekay under the name of Carcharias ca'riileus. This description has been 

 referred by Professor Gill to the synonymy of the very diflerent si)ecies, 

 Carcharias phcmheus {Nardo) = Carcharias milherti M. & H., and has 

 been called ^'■Eulamia milberti''\ 



There is, however, no good evidence that C. milherti {plumhcus) has 

 ever been taken in our waters. The only record is that of INIiiller & 

 Henle, who mention " ein Exemplar in Paris, von New York durch JMil- 

 bert". This specimen is apparently not the type of the original descrip- 

 tion; it belonged to a collection in which there were several confusions 

 of localities, and if really from New York it may have belonged to some 

 si)ecies different from the type in the museum at Berlin — perhaps to 

 C. obscurus or cceruleus. 



There are aj^parently seven species of Carcharias (in the broad sense in 

 which the genus is understood by Midler & Henle, Giinther, etc.,) now 

 known to inhabit the waters of the Atlantic and Gulf coasts of the 

 United States. If others exist, their occurrence is yet to be verified. 



These are, 



1. C. glaucus (L.) Cuv. 



2. * C. ohscurus (Le S.) M. & H. {Platypodon.) 



*The first four of these species may be readilj' recognized by the following char- 

 acters : 



a. First dorsal inserted nearer veutrals than pectorals. {Carcharias). 



Glaucus. 

 an. First dorsal inserted close behind pectorals. 



b. Upper teeth oblique, very deeply notched on the outer margin ; pectorals, 

 long. {I'latypodon Gill) Obscukus. 



th. Uijper teeth suberect, triangular, scarcely notched. {Eiilamia GUI.) 



c. Snout moderate ; its length from mouth uot less than width of mouth. 



CCERULKUS. 



cc. Snout very short; its length from mouth much less than width of 

 mouth \ Platyodon. 



