Cope.] 684 [May 17, 
ter of the eye as seen through its adipose covering is a little less than 
one-fifth the length of the head; and is one-half the interorbital width 
measured over the strong convexity of the frontal bone. The maxillary 
bone makes an angle with the premaxillary, and extends as far as the line 
of the anterior border of the orbit ; the greater part of its length passes be- 
neath the edge of the preorbital bone. The opercular apparatus is elon- 
gate, but the operculum is deeper than long. Total length M. .205 ; length 
of head .047; length to origin of dorsal fin (axial) .082; do. of ventral 
.090; do. of anal fin .134. 
Color in spirits steel blue, paler below ; base of the caudal fin extensively 
black ; other fins unspotted. Sides of head golden; chin and top of head 
black ; a golden speculum above the orbit. 
Coll. of 1877. , 
54. CURIMATUS ALTAMAZONICUS, Sp. nov. 
This is a robust species with small scales. The form is elongate-oval, 
and the head wide. The pectoral region is not flattened nor covered with 
roughened scales, while the ventral line from the ventral fins to the vent is 
keeled, but not serrate. The dorsal fin is elevated, its anterior rays being 
four-fifths as long as the head. 
Radii; D. I. 10; A. 1.12; V.9; P. 13. The pectorals do not reach the 
ventrals, nor the latter the vent. The ventrals originate below the fifth 
dorsal spine. First dorsal ray much nearer the end of the muzzle than the 
base of the caudal fin. Scales 25-94-22. Depth at first dorsal ray entering 
length minus caudal fin 2.7 times. Length of head in the same three and 
two-fifth times. The eye enters the length of the head four and four-fifth 
times, and twice in the mederately convex interorbital width. Lips equal, 
the inferior closing within the superior. Maxillary bone short, not extend- 
ing behind the line of the nares. Color silvery without spots on the body 
or fins. Total length M. .200; length of head .049 ; do. to origin of'dorsal 
fin (axial) .070 ; do. to origin of ventrals .080 ; to origin of anal fin . 124. 
This species appears to be nearest the @. latdor Spix. judging from de- 
scriptions. In that fish the anal rays are said to be 14-15, and the dorsals 12. 
Coll. 1873. 
55. CURIMATUS SPILURUS, Giinth. Steind. 
Coll. 1873. 
56. CURIMATUS TRACHYSTETHUS, sp. nov. 
This is a moderately elongate species with the preventral region flat- 
tened, and covered with large, thick striate and dentate scales ; and with 
the postventral region also flattened, and without distinct median keel. 
Radial formula D. I. 10; C. 241942; A. I. 8; V.9; P.16. The pec- 
torals nearly reach the ventrals, which originate below the middle of the 
dorsal fin, and reach to the vent. The anal fin has a short basis which is 
equal to its distance from the vent ; folded backwards it reaches the base 
of the caudal fin. The elevation of the dorsal fin exceeds the length of the 
head. The depth at the front of the dorsal fin is one-third the length of the 
caudal; the length of the head is one-fourth the same. 
