FISHKS — CYPBINIDAE — TIQOMA BICOLOR. 



289 



1. TIGOMA CONFORMIS, Orel. 



SrEC. Char — Body rather short, siib-fusiforin in its outlines. Head of moderate development, constituting the fourth of the 

 total leng'lL Mouth rather small, with its gepe somewhat oblique ; posterior extremity of maxillar bone e.xtending to a vertical 

 line drawn behind the nostrils. Eye moderate sized; its diameter entering nearly five times in the length of the side of the head. 

 Isthmus small. Anterior margin of dorsal fin nearer the fork of the caudal than the extremity of the snout. Origin of ventrals 

 nearer the isthmus than the insertinn of the caudal. Scales well devel-iped. Pur|>lish brown above ; dark yellowish beneath. 



SvN. — Lavinia conformis, B. & G. in Proc. Acad. Nat. Sc Philad. VII, 1854, 137. 

 Tigoma conformis, Grd. in Proc. Acad. Nat. Sc. Philad. Vlll, 1856, 206. 



Only one specimen of this species was obtained ; its total length being about four inches. It 

 has a quite compact tail. The general appearance of the fish is suggestive of Lavinia crasd- 

 cauda ; the body is deeper and proportionally less elongated ; the eye much smaller, and the 

 scales larger. Another distinctive mark between these two fishes consists in the position of the 

 ventrals, the insertion of which, in T. conformis, is situated in advance of the anterior margin 

 of dorsal, whilst it is placed slightly behind it in Lavinia crassicauda. 



The dorsal fin is higher than long ; its upper edge being sub-convex. The anal, which is 

 likewise deeper than long, is sub-truncated or slightly convex upon its external edge ; its 

 anterior margin is somewhat nearer the isthmus than the tip of the inferior lobe of the caudal. 

 The ventrals are small, sub-ovate, posteriorly rounded ofl', and reaching the anal orifice. The 

 pectorals are likewise small and sub-ovate in their outlines, their extremities not extending as 

 far as the origin of the ventrals. 



D 1, 8 4- 1 ; A 2, 9 ; C 7, 1, 9, 9, 1, 8 ; V 1, 8 ; P 16. 



The scales are well developed, smaller on the dorsal region than along the sides, and smaller 

 still on the belly than on the back. They are somewhat deeper than long, anteriorly sub- 

 truncated and rounded upon the remaining edges, with radiating furrows upon their posterior 

 section only. The lateral line is deflexed upon the middle of the flanks and nearer the insertion 

 of the ventrals than the base of the dorsal. 



The upper region of the head and body is dark purplish brown, lighter on the sides, and dark 

 yellowish beneath, with metallic reflects. The fins are somewhat greyish yellow, the vertical 

 being darker than the horizontal ones. 



List of specimens. 



2. TIGOMA BICOLOR, Grd. 



Spec Char. — Body elongated, anteriorly compact, diminishing posteriorly. Head well developed, constituting somewhat 

 less than the fourth of the total length Mouth large ; posterior extremity of maxillary extending to a vertical line drawn at 

 the anteior rim of the orbit. Eye moderate ; its diameter entering six times in the length of the side of the head. Origin of 

 ventral fins placed slightly in advance of the anterior margin of the dorsal, which is nearer the insertion of the caudal than the 

 extremity of the snout. Scales large. Dorsal region bluish grey ; sides and belly silvery white, sometimes golden. 



SYti.— Tigoma bicolor, Grd. in Proc. Acad. Nat. Sc. Philad. VIII, 1856, 206. 



37 a 



