276 



U. 8. P. R, R, EXP. AND SURVEYS ZOOLOGY GENERAL REPORT. 



This species is somewhat allied to M. lutrensis, from which it differs by a shorter snout and a 

 more compact tail. The eye is large also. A distinctive feature between the two species is to 

 be found in the squamation, since the scales are more deeply imbricated in M. lutrensis than in 

 31. pulchella. The vertical fins are well developed, whilst the horizontal ones are of but 

 moderate development. The caudal is deeply furcated, and somewhat longer than the head, 

 since it enters four times and a half in the total length. The dorsal and the anal are sub- 

 trapezoid, the upper edge of the dorsal being sub-concave, whilst the inferior edge of the anal 

 is nearly linear. The base of the latter fin is somewhat longer than that of the former, and 

 the anterior margin of the anal is nearer the isthmus than the fork of the caudal. The origin 

 of the ventrals is nearer the extremity of the snout than the insertion of the caudal. These 

 fins are posteriorly rounded off, and their tips reach the vent when bent in that direction. The 

 pectorals are sub-ovate ; their tips not extending as far as the insertion of the ventrals. 

 D 2, 8 -f 1 ; A 2, 9 -f 1 ; C 8, 1, 9, 8, 1, 9 ; V 1, 8 ; P 13. 



The scales are large, sub-truncated anteriorly where deepest, and rounded upon the remaining 

 edges, with numerous radiating furrows upon their posterior section. 



The dorsal region is reddish brown and the abdominal region brownish yellow, whilst the 

 middle of the sides exhibits an argentine tint. The dorsal and caudal are greyish yellow ; the 

 other fins being yellowish. 



References to the figures. Plate LVIII, fig. 11, represents Montana pulchella, size of life. 

 Fig. 12 is a section of the body taken across the line of greatest depth. Fig. 13, a dorsal 

 scale. Fig. 14, a scale from the lateral line. Fig. 15, a scale from the abdominal region. 



List of specimens. 



6. MONIANA FKIOIDA, Grd. 

 PLATE LIX, FIGS. 1620. 



SPEC. CHAR. Body somewhat elongated, sub-fusiform. Peduncle of tail stoutish. Head constituting 1 a little less than the 

 fifth of the entire length. Snout sub-conical ; upper jaw overlapping the lower. Posterior extremity of the maxillary extending 

 to a vertical line drawn behind the nostrils. Eye moderate sized and circular ; its diameter entering nearly four times in the 

 length of the side of the head. Anterior margin of dorsal fin nearer the insertion of the caudal than the tip of the snout. 

 Horizontal fins of moderate development. Rcddisli brown above ; yellowish or whitish beneath. 



SYN. Moniana frigida, GRD. in Proc. Acad. Nat. Sc. Philad. VIII, 1856, 200. 



This species is a little more than three inches in total length, and stands next to the largest 

 of the hitherto known species. The head forms about the fifth of the length. The body is 

 rather deep and very much compressed ; the caudal fin deeply furcated. The eye is circular, and 

 its diameter contained four times in the length of the side of the head. The upper edge of the 

 dorsal fin is linear ; the lower edge of the anal, sub-concave. The anterior margin of the 



