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INDIAXA rXIYERSITY STUDIES 



GENYCHARAX gen. nov. 



A geuiis allied to the Tetragonopteriiiae on the one hand, and to Ex- 

 odon on the other. Its month a dnplicate of that of the Tarpon. 



Origin of dorsal midway, or hnt slightly behind midway, between 

 snout and caudal. Anal comparatively short, its origin behind the vertical 

 from last dorsal ray. Pectorals uot overlapping ventrals. Mouth large, 

 oblique, the tip of the lower jaw entering the profile, the deutary teeth 

 engaging the outer series of the premaxillary teeth. Maxillary very large. 

 A few teeth in a single series on the upper part of the maxillary. Pre- 

 maxillary with two series of teeth, those of the outer series numerous, 

 small, forming a compact series directed forward and slightly upward. 

 Teeth of the inner series much larger (not more than 6) and fewer, 

 directed downward. Dentary with about 6 large, recurved teeth in the 

 transverse series, the series continued on the sides by over 20 graduate, 

 incurved teeth. Teeth all unicuspid, triangular. 



Lateral line complete. Adipose fin well developed. 



Type, the single known species. 



23. Genycharax tarpon sp. nov. 



Head 3.4; depth 2.75-3: D. 11; A. 23-25; scales 10 to 12-56 to 68-10 

 to 12. Eye equal to snout, 4 in the head ; interorbital 3-3.5 in the head. 



Elongate, subrhomboidal : profile depressed over the eyes. Ventral and 

 predorsal regions rounded, without distinct median series of scales. Inter- 

 orbital broad; frontal frontanel triangular, 1.5 in the parietal, as wide as 

 latter at its posterior end. Maxillary extending beyond the second sub- 

 orbital, to below the posterior edge of the head. Third suborbital in con- 

 tact with the preopercle behind, leaving a wide naked area below. Four 

 maxillary teeth ; about sixteen teeth in front row of premaxillary, six in 

 second row (one tooth between the outer ends of the two rows) ; about 

 twenty-eight teeth in the dentary. Gill-rakers 6 + 11, the longest nearly 

 half length of eye. 



Dorsal small, its highest rays not reaching half-way to the caudal. 

 Lower caudal lobe a little the longer, equal to head less opercle; anal 

 rather low, but slightly emarginate, the tip of the highest ray reaching 

 but little beyond the base of the lowest, somewhat beyond the middle of 

 the fin. Ventrals not reaching the anal; frequently not beyond the anus. 

 Pectorals sometimes reaching the ventrals, usuallj^ much shorter. 



Fins all naked; only a sheath of one row of scales along base of anal 

 anteriorly. Axillary scale well developed, but short. Scales all cycloid, not 

 conspicuously regular in arrangement. Lateral line decurved to above last 

 fourth of the pectorals, thence straight. - 



A plumbeous lateral band, slightly expanded upon the caudal peduncle, 

 but only faintlj^, or not, continued on the caudal fin : a vertically elongate 

 humeral spot; anal and caudal lobes yellow or orange. 



Stomach very large, (distended with locusts) coecal, about seven large, 

 pyloric coeca. Entire canal not quite equal to the total length. Air- 

 bladders large, the anterior subcubical, one-half longer than the eye, about 

 four-tenths the length of the conical, posterior bladder. 



A game fish of the upper Cauca river. 



