NO. lO FISHES FROM PERU HILDEBRAND AND BARTON 5 



marginal pale streak anteriorly, becoming marginal over the mid- 

 caudal section, soon fading into the general pale brown color of the 

 posterior section of the fin. 



This species is represented by a single specimen (U.S.N.M. No. 

 144253) 510 mm. in total length. Its chief distinguishing characters 

 are shown in the parallel comparison of the three species of this genus 

 herein recognized, which follows the description of P. angusticeps. 



The name serratidens is in reference to the serrated teeth in the 

 jaws. 



PRIODONOPHIS ANGUSTICEPS, new species 

 Figure 2 



Body with wrinkled skin, compressed, its thickness at vent a little 

 less than three-fourths its depth at same place ; tail more strongly 

 compressed, becoming strongly compressed and broadly rounded dis- 

 tally; length anterior to vent equal to length of rest of body; head 

 deep, rather strongly compressed, its width just in front of gill open- 

 ing equal to about half its depth at same place, its length anterior to 

 gill opening 6.4 in total length and 3.25 in length anterior to vent ; 

 greatest depth (at gill opening) 6.6 in length anterior to vent, 2.0 in 

 head ; snout fairly robust, not much deeper than broad, about square 

 in cross section, 6.1 in head; eye small, 11.4 in head, 1.85 in snout; 

 mouth very large, horizontal, the gape extending about half its length 

 beyond middle of eye, 2.3 in head; lips with small papillae; upper 

 lip and low^er jaw with prominent pores; teeth in jaws in a single 

 series, rather small, not prominently compressed, with finely serrated 

 margin visible only under magnification, none on vomer or palatines ; 

 anterior nostril with a tube about two-thirds length of eye, situated 

 well above margin of upper lip, posterior nostril a roundish pit sur- 

 rounded by a slightly raised membrane, situated near edge of dorsal 

 surface of snout just in advance of vertical from anterior margin of 

 eye ; gill opening an oblique slit, nearly twice diameter of eye ; dorsal 

 fin high, more than twice as high as the anal, its greatest height about 

 equal to length of snout and eye, fully confluent with the caudal and 

 anal, its origin from tip of snout 4.9 in length anterior to vent ; caudal 

 fin broadly rounded. 



General color rather light chocolate brown, the furrows of the 

 wrinkled skin dark brown, mostly horizontal on head and vertical on 

 body, some wavy or even slightly cross hatched, disappearing on distal 

 part of tail; fins of about same color as body, dark lines following 

 the furrows of the wrinkles in the skin, paralleling the rays. 



This apparently new eel is represented in the collection by a single 

 specimen (U.S.N.M. No. 144254), 510 mm. in total length. The 



