Cope. | 678 [May li, 
Char. Specif. The proportions are elongate and the head is short, enter- 
ing the length less the caudal fin six times. The anal fin is long, extend-- 
ing far forward, and the greatest depth of the fish is at its anterior part. 
This is a little more than one-fifth the length (less the caudal fin). The 
head is narrow, and rises rather steeply to the base of the dorsal spine 
without interruption. The supraoccipital process is rather wide, and con- 
tinuous with the basal bone of the dorsal spine. The latter is bifurcate and 
sends a process outwards and backwards behind the base of the spine. The 
frontal fontanelle is long, and the head is covered with smooth skin. The 
eye is large and without free dermal border ; its diameter enters the length 
of the head to the opercular border three and one-third times, and the inter- 
orbital width one and two-third times. The superciliary and prefrontal 
borders are prominent and form togetheran acute angle. The supraoccip- 
ital region is not keeled, but its sides form a steep roof. 
Radii D. I.; A. 61; C. + 17 +4-; V.15;P. 1.18. The dorsal spine is 
slender and nearly as long as the pectoral. It is directed somewhat for- 
wards, and is entirely smooth. The caudal fin is notched to half its depth, 
and is rather small. The ventrals are large, and are united by the entire 
length of their inner rays. The external or first ray of each, is larger than 
the others, and the apex of the fin reaches the first anal ray. The closed 
pectoral spine barely reaches the base of the ventral; it isset with recurved 
teeth behind, but is smooth in front. The soft part of the fin is contracted 
and is much smaller than that of the ventral fin. The humeral process is 
short and smooth and is covered by a smooth skin ; the postcoracoid pro- 
cesses are rather long and are very acute at the apex. 
The maxillary barbels continue from the extremity of the long maxillary 
bone to the middle of the pectoral spine; the anterior ventrals, which are 
very little in advance of the posterior ventrals, reach the base of the same. 
The eyes have nearly as much inferior as superior range, and the mouth does 
not extend beyond their anterior angle. Lips equal. 
Color in spirits light brown, the dorsal region blackish. A black spot in 
the middle of each lobe of the tail. Total length M. .125; length of head 
.019 ; to the base of anal fin .046; of anal fin .062. Width between bases 
of pectoral spines .016. 
Two specimens from the collection of 1873. 
21. CETOPSIS CANDIRA Agass. 
Coll. of 1877. 
22. RArNODORAS PRIONOMUS Cope, Proceed. Academy Philada. Septem- 
ber 1874, p. 134. Rhinodoras teffeanus Steindachner, Sitzungsberichte 
Akademie Wiss. Wien, 1875; read January, published ? Pl. III. 
From Nauta, Coll. 1873. 
3. RHINODORAS NIGER Valence. ¥ 
Coll. 1873. Nauta. 
24. ZATHORAX NAUTICUS Cope, Proceed. Acad. Phila. 1874, p. 138. 
From Nauta. 
In some specimens of this species the adipose dorsal fin is wanting, 
