242 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



.men examined by us, the pectoral is much hirger than in the descrip- 

 tion and figure of the hitter, published by Miiller & Henle. 



A single individual of Isurus dekayi, a female ten feet in length, was 

 fonnd on the beach of Santa Rosa Island, near Pensacola. It showed 

 the following characters : 



Color dark sooty-gray above, white below, the color abruptly chang- 

 ing on the tail. The whole of the caudal, the dorsal and upper edge of 

 pectoral, dark. Anal and under side of pectoral white. 



Head 5 in total length with caudal, the upper lobe of caudal 5i in the 

 same. Pectoral fin falcate, as long as head; front of dorsal inserted 

 well behind axil of pectoral, at a distance equal to ^ the head or a little 

 more than half the dorsal base, which is 2^ in head. Height of dorsal, 

 If in head. Distance from posterior edge of base of dorsal to front of 

 ventral, If in head. Dorsal and pectoral somewhat falcate. 



Second dorsal very small, in front of the slightly larger anal, and not 

 twice as large as eye. Interspace between dorsals, 2f times base of 

 first dorsal. 



Gill area deeper than long; its depth 2f in length of head. Snout 

 sharp, conical. Eye large, 4f in snout, wliich measured from eye, is 3 

 in head. Nostril half nearer eye than snout; eye slightly nearer tip of 

 snout than angle of mouth. Labial fold very short. Caudal keel 

 strong, a pit above and below it. 



Greatest depth of body, three-fourths length of head. Teeth about 

 ffj none of them with basal cusps; those of the middle of each jaw 

 mnch longer and narrower than the others, as in other species of the 

 genus. 



CAECHARIID^. 



2. Carcharias,* m). incert. Sharp-nosed Shark, G. 



The jaws of an unknown species of shark were obtained at Galveston. 

 The teeth in the upper jaw are narrowly triangular, little oblique, and 

 slightly notched on the inner side. Median teeth smaller and narrower 

 than those on the sides. Bases of the teeth coarsely serrate, especially 

 on the inner edge; crown of the teeth finely serrate. Lower teeth very 

 narrow, nearly erect, their edges very minutely serrulate, appearing 

 entire, except under a lens. Teeth about |f. 



* The name Carcharias first appears in Rafinesqne's Caratteri di Alcnni auovi Generi, 

 etc., 1810, 10. Only neiv species nre noticed iu this paper, and but one is nieiitioued. 

 Ca7-charias taurus Raf., a species of Odontaspis Ag., which does not agree with the orig- 

 inal diagnosis of Carcharias. In Rafinesqne's Indice d' Ittiologia Siciliana, IHlO, j). 44, 

 a work which appeared almost simultaneously with the preceding, we find three species 

 mentioned under the head of Carcharias, viz, lamia, glaacus, taurus. It seems evident 

 from the context that the former species was intended by Rafiuesque as the type of the 

 genus C rcharias. It is, however, not described .and not identifiable, although the 

 species called later " Carcharias lamia" by Risso, was probably intended. In view of 

 the fact that nearly all modern writers have adopted the name Carcharias toT the genus, 

 to which glaucus and ^^ lamia" belong, it seems to us that Cuvier's restriction of the 

 name Carcharias may be retained, in spite of the evident objection to it. If Carcharias 

 be retained, C glaucus should be considered its type, being a species certainly iden- 

 tified and agreeing with the original diagnosis of the genus, with Avhich C. taurus 

 was associated by error, an error several times since repeated. The two papers of 

 Rafiuesque may well be considered as parts of the same memoir, the "Caratteri'" con- 

 taining an account of "new" siJccies, " the Indice" an enumeration of known species. 



