292 



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



By its general aspect this species resembles T. lineata, whilst its structural characters are 

 suggestive of T. liumboldti. The dorsal and anal fin are nearly equal in size and shape ; the 

 upper edge of the former and the inferior edge of the latter are slightly sub-concave. The 

 anterior margin of the anal is nearer the tip of the inferior lobe of the caudal than the isthmus; 

 its base enters nine times in the total length, the caudal fin excluded. The ventrals are 

 posteriorly sub-truncated ; their tips not extending to the vent. The pectorals are rather 

 slender, sub-ovate in their outline, their extremities not reaching the origin of the ventrals. 

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



The scales are about as large as in T. liumboldti, and the lateral line is almost identical in its 

 direction. Its system of coloration is likewise very similar to that of the species just alluded 

 to. Dorsal region bluish black with a metallic reflect ; middle of the flanks yellow, with 

 numerous black dots constituting two dark zones, one above, the other below the lateral line, 

 between which zones may be observed two streaks of red or golden orange. The belly exhibiting 

 a uniform metallic yellow tint. The dorsal and caudal fins being greyish, whilst the remaining 

 fins are more of a yellowish tint. 



List of specimens. 



6. TIGOMA LINEATA, Grd. 



SPEC. CHAR. Body elongated, sub-fusiform. Head forming a little less than the fourth of the total length. Snout sub- 

 conical ; gape of the mouth somewhat oblique ; lower jaw slightly overlapped by the snout. Posterior extremity of maxillar 

 bone extending to a vertical line drawn at the anterior rim of the orbit Eye moderate, sub-circular ; its diameter entering 

 nearly five times in the length of the side of the head. Anterior margin of dorsal fin somewhat nearer the extremity of the 

 snout than the tip of the upper lobe of the caudal. Origin of ventrals nearer the extremity of the snout than the fork of the 

 caudal. Scales Email. Bluish brovn streaks above ; uniform yellowish beneath. 



SYN. Tigoma lineata, GRD. in Proc. Acad. Nat. Sc. Philad. VIII, 1856, 206. 



The general aspect is elongated, the body being sub-fusiform, anteriorly thickish, and quite 

 tapering posteriorly. The head is small and conical, constituting somewhat less than the 

 fourth of the total length. The dorsal and anal tins are rather narrow ; their external margin 

 being slightly sub-concave. The anal itself is smaller than the dorsal, and its anterior margin 

 is nearer the tip cf the inferior lobe of the caudal than the isthmus ; its own base entering 

 more than thirteen times in the whole length. The ventrals are small, posteriorly rounded, 

 sub-ovate, not quite reaching the vent. The pectorals are moderate sized and posteriorly 

 rounded ; their extremities being far from extending to the origin of the ventrals. 

 D 1, 8 ; A 1, 8 + 1 ; 6, 1, 9, 8, 1, 6 ; V 1, 9 ; P 15. 



The scales are proportionally small ; the lateral line describing an open downwards curve, 

 remaining below the mesial line even along the peduncle of the tail. 



The ground color is yellowish ; the centre of the scales of the upper regions being black, the 

 back and upper half of the flanks appear as if marked with alternate lines of black and yellow. 

 The belly is unicolor. The dorsal and caudal are greyish olive ; the other fins, yellowish. 



