1878.] 6385 [Cope. 
The eye is large, eritering the length of the head 3.25 times and the flat 
interorbital space 1.5 times. The muzzle is flat and projects a little beyond 
the lower lip. The mouth does not extend to the line of the orbit. The 
inferior suborbital hone is much longer than the others. Total length M. 
-128 ; length of head .026; to base of dorsal .040; of ventral .047; of anal 
080. Scales 848-6. 
Color silver, with bluish reflections above ; a bright line along the middle 
of each row of scales. Fins immaculate except a round spot on the dorsal 
fin below its middle. 
This species is allied to the C. asper of Gunther, but that fish has smaller 
scales, more anal rays and other characters. (See Proceed. Zool. Soc. 
Lon., 1868.) 
Coll, of 1877. 
57. POTAMORHINA PRISTIGASTER: Curimatus pristigaster Steindachner, 
Sitzungsberichte Akad. Wiss. Wien, 1876, July (separata p. 25), Pl. VI. 
This species, well described and figured by my friend Dr. Steindachner, 
is too distinct from the species of Curiématus to remain in that genus, in my 
opinion. It presents between the ventral and anal’ fins not only a keel, 
as in many species of the genus named, but the keel is surmounted by a 
series of acute recurved spiniform scales, quite unlike the normally formed 
ones which bound it in the keeled species of Curimatus. I therefore pro- 
pose for it the generic name above written. The spinous processes are 
stronger in-my specimens than in the figure given by Dr. Steindachner. 
Coll. 1878. 
58. PROCHILODUS ORTONIANUS, Sp. nov. 
Radial formula D. I. 10; C. 8-19-2 ; A. III. 8; V.9; P. 14. Scales 9-44-7. 
Depth of body at dorsal fin entering the length less the caudal fin 3, times; 
Length of head entering the same 3.7 times. Diameter of eye entering 
head 4.5 times, or one and a half times in the muzzle and two and a half 
times in the interorbital width. From these figures it is evident that this 
isa moderately elongate species, with rather elongate and wide head. The 
frontal region is convex, and the upper lip does not project beyond the 
lower as in P. harttid Steind. The pectoral fins reach the ventrals, but 
the latter fall far short of the anus. The belly between the latter and the 
pase of the ventral is keeled, but not serrate. The dorsal fin is situated a 
little in advance of the ventrals, and is quite elevated, equaling the length 
of the head. Caudal fin rather short and robust. Total length M. .200 ; 
length of head .046 ; do. to base of dorsal (axial) .072 ; do. to ventral (axial) 
.088; to base of anal .134; depth of caudal peduncle .020. 
Color silvery, above shaded with blackish ; the scales at the base of the 
anal fin inserted in a blackish skin. Dorsal fin with six or seven cross- 
rows of blackish dots, which only mark the rays. Caudal fin with four 
cross-bands of rather obscure character, which follow the posterior contour 
of the fin, except the posterior, which cross the apices. A large specimen, 
measuring M. .350, is uniform silvery everywhere. 
From Nauta, Peru, coll. 1873. 
