476 ~—sCDr.. A. Giinther on some new Freshwater Fishes 
Callichthys armatus. 
This species belongs to the group with compressed head. 
Dorsal spine as high as the body, finely serrated behind ; 
pectoral spine rather stronger but shorter than that of the 
dorsal, longer than the head. Anal spine shorter and more 
feeble than that of the adipose fin. Olive-coloured (in spirits), 
the nine or ten anterior scutes with vertical series of small 
blackish spots. 
Xeberos and Huallaga. 
Cheetostomus Fordit. 
Head much depressed, elongate, its length being one-third 
of the total (without caudal). Eye small, one-eighth of the 
length of the head, and two-fifths of the width of the inter- 
orbital space, which is rather flat. Each jaw with six or seven 
stoutish teeth on each side; each of them has a lobe on its 
outer side, rather distant from the brown flat apex. Throat, 
thorax, and belly: naked. The first ray of the dorsal and anal, 
and the upper and lower of the endl, slightly thickened and 
rough. Pectoral spine strong, extending to the second third 
of the ventral fin, covered with short hooks. Each scute of 
the body with a series of three or four very prominent spines. 
Ten scutes between anal and caudal, and eight between the 
two dorsal fins. Brownish black ; most of the scutes have a 
round bluish-white dot at the base; lower parts with nume- 
rous similar but more distinct white dots. 
Surinam. 
Chetostomus depressus. 
Head and trunk much depressed and flattened. The length 
of the head is rather more than one-third of the total (without 
caudal) ; the diameter of the eye is one-fifth of the length of the 
head, and two-thirds of the width of the interorbital space. The 
margin of the snout is covered with short bristles ; interoper- 
culum with a bundle of about eight similar bristles, the longest 
being only half as long as the eye. The lower side of the 
head, thorax, and belly entirely naked. Pectoral spine ex- 
tending to the second third of the ventral, and rather rough ; 
eleven scutes between the anal and caudal fins. Scutes with 
numerous striz, each stria composed of numerous very small 
spines. Brown; each scute with several round, very small, 
whitish dots; dorsal and caudal rays with a series of similar 
dots, the interradial membrane being immaculate. 
Surinam. 
Cheetostomus megacephalus. 
Head but slightly depressed, rather longer than broad, its 
5 Se 
