30 Dr. A, Giinther on some Fishes from the Amazons. 
VII.—Remarks on some Fishes from the River Amazons in the 
British Museum. By Dr. Auzerr GUNTHER. 
A coxurction of fishes made by Mr. Bartlett, junr., on the 
Upper Amazons, and acquired for the British Museum, con- 
tained, besides numerous examples of described species, a few 
which appear to be new to science*. It afforded me also the 
opportunity of comparing the true Prochilodus mgricans of 
Agassiz with its congener from the Essequibo River (cfr. Fish. 
v. p. 295). They prove to be specifically distinct, the species 
from the Amazons having somewhat smaller scales, viz. L. lat. 48. 
L. transv. 10/9. The height of the body is one-third of the 
total length (without caudal). The name nigricans must be 
retained for the Amazons species, whilst the Essequibo fish is 
most probably identical with P. rubroteniatus (Schomb.), 
Tetragonopterus Bartletti, n. sp. 
Didi, A. Sl. Lh. lat. 39. i. transy.. 87% 
The height of the body is contained twice and three-fourths 
in the total length (without caudal), the length of the head 
thrice and two-thirds. Interorbital space convex, its width 
being scarcely more than the diameter of the eye, which is one- 
third of the length of the head. The upper profile of the head 
is very slightly concave. The maxillary extends a little behind 
the vertical from the front margin of the orbit. The origin of 
the dorsal fin is immediately behind the base of the ventrals. 
Pectoral extending beyond the base of the ventrals, nearly to the 
vertical from the origin of the dorsal. Humeral and caudal 
spots distinct ; body without silvery band. One of the speci- 
mens has a broad oblique dark band across the middle of the 
dorsal fin. 
Two specimens, 4 inches long, were in the collection. 
Cynodon pectoralis, » sp. 
This species is closely allied to C. scombroides, but has a 
greater number of rays in the anal fin, and a much longer and 
larger pectoral fin. 
Daa A, a8. Pras, V1 0: 
The height of the body is two-sevenths of the total length 
(with the caudal), the length of the head nearly one-fifth. 
Scales very small, those of the lateral line about twice the size 
* I observe, in a letter of Prof. Agassiz, addressed to and published by 
M. Milne-Edwards, that a new genus of freshwater Belonide from the 
Amazons is mentioned. I suppose this to be the same fish which was dis- 
covered by Mr. Bates some fifteen years ago, and is described in the ‘ Catal. 
Fish.’ vi. p. 256, as Potamorrhaphis (Belone) teniata, 
