NATURAL SCIENCES OF PHILADELPHIA. 



21b 



Total length . 

 Length to orbit 



" " opercular slit 

 " ventral fin 

 " anal fin 

 " caudal fin 

 of dorsal spine 

 " pectoral spine 

 " postcoracoid 

 Width of muzzle . 

 " at humeral knobs 

 " "1st lateral shield 

 Expanse of both pectoral spines 



4( 



a 

 it 

 (( 



M. 



0.035 

 .0015 

 .007 

 .015 

 .0189 

 .028 

 .0075 

 .0123 

 .0082 

 .005 

 .013 

 .003 

 .081 



Ambyiacu River, Equador. John Hauxwell. 



The preorbital comb is like that of Doras pectinifrons, Cope, 



from the same region. 



CALLICHTHYS ASPEE, Q. Gaim. 



Giinther, v. 225. 



CALLICHTHYS MELAMPTERUS, Cope, sp. nor. 



The head depressed, muzzle broadly rounded. Bodj' strongly 

 compressed ; the dorsal line rising steeply and continuously with 

 the profile, to the dorsal fin. Caudal region much compressed ; 

 tail openly emarginate. Inferior lip little reverted, bearing no 

 barbels; tip of the muzzle projecting but little bej^ond the mouth. 

 Inferior barbel extending to near the end of the ventral fin, supe- 

 rior to near the end of the pectoral. Lateral shields 25-24, from 

 supraclavicle. Azj^gous plates 5. Radii D. 8, A. 1, 6, V. 7, P. 

 I. 8. Dorsal spine like other rays, pectoral toothed within, and 

 with short tooth-like bristles without. Spine of adipose reaching 

 to basis of caudal. 



Orbit 3.5 times in length of head, twice in interorbital width. 

 Depth of head more than two-thirds length. Length of head one- 

 third length without caudal, equal de^Dth. Length over all, three 

 inches. 



Color dark plumbeous ; the preorbital region, and caudal and 

 inferior fins, black. 



This species is much more compressed than the C asper. Be- 

 sides other points, there is one more pectoral ray and a diflferent 



1872.] 



