274 



U. S. P. R. R. EXP. AND SURVEYS ZOOLOGY GENERAL REPORT. 



trapezoid in their outline, the anal being somewhat longer than the dorsal, and, likewise, deeper 

 than long. &quot;Both of these fins are sub-concave upon their external edge ; the anterior margin 

 of the anal is equidistant between the isthmus and the fork of the caudal. The ventrals are 

 obtusely rounded upon their posterior margin ; their tips overlapping the vent and reaching the 

 origin of the anal. The pectorals are sub-lanceolated ; their extremities not extending as far 

 back as the insertion of the ventrals. The rays are : 



D 2, 9 + 1 ; A 2, 9 + 1 ; C 5, 1, 9, 8, 1, 7 ; V 1, 8 or 9 ; P 16. 



The scales are remarkably deep, rather sub-truncated anteriorly, rounded posteriorly, and 

 rather tapering superiorly and inferiorly. 



The upper region is greyish brown, whilst the flanks and the abdomen are dull yellowish or 

 whitish, with a somewhat metallic reflect. The dorsal and caudal are greyish yellow ; the rest 

 of the fins light sulphur yellow. 



References to the figures. Plate LIX, fig. 6, represents Montana leonina, size of life. Fig. 7 

 is a section of the body taken across the line of greatest depth. Fig. 8, a dorsal scale. Fig. 

 9, a scale from the lateral line. Fig. 10, a scale from the abdominal region. 



List of specimens. 



3. MONIANA DELICIOSA, G r d . 



SPEC. CHAR. Body slender and elongated. Head constituting the fifth of the total length. Snout sub-conical ; upper jaw 

 overlapping the lower. Posterior extremity of the maxillary extending to a vertical line drawn between the nostrils and the 

 orbit. Eye large and circular ; its diameter entering three times in the length of the side of the head. Anterior margin of 

 dorsal fin equidistant between the tip of the snout and the insertion of the caudal. Pectorals and ventrals slender and of 

 moderate development. Reddish brown above ; yellowish beneath ; middle of flanks silvery. 



SYN. Moniana delitiosa, GRD. in Proc. Acad. Nat. Sc. Pliilad. VIII, 1856, 199. 



This is one of the most slender of all the species hitherto known of the genus. Its length 

 is a little over two inches and a half, the head forming the fifth part of it. The latter is 

 proportionally small, sub-conical anteriorly. The eye is quite large and circular, its diameter 

 entering about three times in the length of the side of the head. The dorsal is much higher, 

 and the anal much deeper, than long ; the anterior margin of the anal is nearer the tip of the 

 lower lobe of the caudal than the isthmus. The origin of the ventrals is equidistant between 

 the tip of the snout and the insertion of the caudal ; they are posteriorly sub-truncated, their 

 extremities extending as far as the vent. The pectorals are slender, sub-ovate in their outline, 

 and, in being brought alongside the body, they do reach the insertion of the ventrals. The 

 caudal is deeply furcated, longer than the head, arid contained four times and a half in the 

 total length. 



D 2, 8 + 1 ; A 2, 7 + 1 ; C 6, 1, 9, 8, I, 7 ; V 1, 8 ; P 13. 



There are ten longitudinal rows of scales upon the greatest depth of the body ; the scales 

 themselves are large. The lateral line being slightly deflextd upon the abdominal region. 



The color of the dorsal region is reddish brown, whilst the abdominal region is yellowish. 

 A silvery streak may be observed along the middle of the flanks above the lateral line, which 



