Durbin : The Expedition to British Guiana. 69 



Occipital process short ; bordered by one to one and one-half scales. 

 Frontal fontanels much narrower than the parietal, about three-fourths 

 the length of the parietal without the occipital groove. Second sub- 

 orbital with narrow naked margins behind and below. Snout short, 

 about one-half the length of the eye ; mouth moderately large. Max- 

 illary less than the eye, 2.75 in the head. Mandible a little more 

 than 2 in the head. 



Premaxillary with two, rarely three, small tricuspid teeth in the 

 outer row, and five broad five- to seven -pointed teeth in the inner row, 

 the tooth at the median end of the inner row of each premaxillary 

 fitting together, so that the two apparently form a single very large 

 median tooth. Maxillary with two or three broad five- and seven- 

 pointed teeth. Dentary with four large seven-pointed teeth followed 

 on the sides by one or two minute tricuspid teeth. 



Scales cycloid, regularly imbricate, strife few, variable in number, 

 no interpolated scales or rows of scales. Caudal naked. Anal sheath 

 of three scales covering the base of the first five or six rays. Lateral 

 line with pores developed on five to eight scales, slightly decurved. 



Origin of the dorsal equidistant from the snout and caudal, its 

 longest ray 3^ into the length. Origin of anal on the vertical from 

 the last two or three dorsal rays. Anal emarginate, the longest ray 

 ii into the base. Ventrals on the vertical from the second dorsal 

 ray. Ventrals just reaching the anal ; pectorals just reaching the 

 ventrals. 



Caudal spot intense black, roundish, and scarcely if at all continued 

 upon the caudal rays. Humeral spot lacking, but the intense narrow 

 black lateral stripe widened somewhat in the humeral region. Scales 

 of the back and sides above the lateral stripe heavily outlined with 

 dusky. All the fins somewhat dusky, but without distinct markings of 

 black or white. Sides over the lateral stripe and below it with a steel- 

 blue iridescence. Preopercle also with blue iridescence. 



Hyphessobrycon eos sp. no v. 



Type, 36 mm. (No. 11 94 Carnegie Museum Catalog Fishes.) 

 Creek between Potaro Landing and Kangaruma. 



Cotypes, 24 specimens, 35 to 42 mm. Creek between Potaro 

 Landing and Kangaruma. (C. M. Cat. No. 1196, a-e ; I. U. Cat. 

 No. 11770.) 



Cotypes, 43 specimens, 19-34 mm. Tukeit. (C. M. Cat. No. 

 1 195, a-j ; I. U. Cat. No. 11 771.) 



