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INDIANA UNIVERSITY STUDIES 



the lower forming a sheath for the detached fulcra ; scales of sides con- 

 tinned to form a basal anal sheath ; fins otherwise naked. 



A silvery lateral band ; a large black spot covers middle of caudal 

 peduncle and base of middle caudal rays; anal dusky; dorsal dusky, but 

 the anterior rays free from black pigment. 



Stomach coecal, six pyloric coeca, the entire alimentary canal shorter 

 than the entire fish. 



Type, 53 mm., male, CM. No. 4806 a, Istmina. 



Paratypes. thirty-six specimens, largest 70 mm., Istnuna, CM. No. 

 4807 a-j ; I.U.M. No. 12671 a-j. 



25. Gephyrocharax caucanus sp. nov. 



Head 5 ; depth 4 ; D. 10 ; A. 34 ; scales 5-44-5 ; eye equal to snt)ut or to 

 interarbltal, 3.3 in head. 



Compressed, much slenderer than in chocoensis, the eye smaller. Dor- 

 sal outline very little arched, the ventral much more so; predorsal area 

 rounded, about 20 scales not arranged in a regular median series; pre- 

 ventral area narrowly rounded, post ventral keeled but obscured in gravid 

 females ; breast narrow, with distinct median ridge ; fontanel long, nar- 

 row ; a minute frontal fontanel ; third suborbital covering entire cheek ; 

 snout pointed, the lower jaw heavy; maxillary-premaxillary border angu- 

 late, about 2.5 in the head ; no teeth on maxillary ; premaxillary with three 

 teeth in outer series, four teeth in the inner ; mandible with three large 

 teeth on each side followed by minute ones on the side. 



Gill-rakers 5 + 11. Dorsal rounded, not nearly reaching adipose ; cau- 

 dal lobes about equal, 4.5 in the length, lower fulcra, in male, free, spinous ; 

 origin of dorsal about midway between middle of pectoral and caudal ; 

 anal slightly emarginate, its origin about midway between caudal and 

 eye (its first ray in the male sometimes short, spinous, free [and erect?]). 

 Ventrals reaching anus, pectorals to middle of ventrals, 4 in the length. 



Scales thin, cycloid, easily lost ; caudal naked, no caudal sheath in the 

 males ; scales of the sides continued on the anal rays at base. 



Silvery, a bright lateral baud ending in a spot on caudal peduncle and 

 base of the middle rays ; no humeral spot. 



Type, 62 mm. 9 , Cartago, CM. No. 4802. 



Paratypes, thirty-six specimens, Cartago, CM. No. 4803 a-j ; I.U.M. No. 

 12668 a-j; fifteen specimens, Paila, CM. No. 4804 a-e; I.U.M. No. 12069 a-e; 

 seven specimens, Call, CM. No. 4805 a-c; I.U.M. No. 12670 a-d. 



Evidently taken near the breeding season (March, 1912), mostly 

 females. 



This species differs notably from its Pacific slope relatives in its more 

 elongate form, heavier lower jaw% more oblique mouth, etc. 



26. Gephyrocharax melanocheir sp. nov. 



Head 4.25; depth 3-3.3; D. 10; A. 31; scales 6-39 to 41-4 or 5; eye 

 .75-.9 in snout, 3 in head, very little less than interorbital. 



Very similar in shape and general appearance to G. chocoensis, the 

 females are scarcely distinguishable but have distinct vertical humeral 

 spot and the bases of the two first dorsal rays are dusky. The males are 



