92 THE AMERICAN CHARACIDAE. 



half times in the distance of its base from the dorsal, and bordered by three 

 scales on each side. 



Groove of the occipital frontanel reaching to tip of occipital process; inter- 

 orbital slightly convex; second suborbital leaving a narrow naked margin of 

 the cheeks; maxillary not reaching to the end of the first suborbital two and 

 three fourths in the head, equal to the distance of the tip of the snout from the 

 pupil. Four teeth in the front row of the premaxillary, the third slightly with- 

 drawn from the line of the others, five graduated teeth in the inner series; maxil- 

 lary with three teeth; mandible with four teeth and numerous small ones on the 

 side. 



Gill-rakers 9 + 14. 



Scales deeply imbricate, each with several divergent striae. Anal sheath 

 of a single series of scales. Lateral line but little descending. A well-developed 

 axillary scale; caudal scales caducous. 



Origin of dorsal in front of middle of body; ventrals nearer tip of snout 

 than the dorsal, equidistant from tip of snout and base of last anal ray or a little 

 nearer the former; pectorals extending little beyond origin of ventrals; ventrals 

 not quite to anal; anal slightly emarginate. 



A vertical humeral spot above the space between the third to the fifth scale 

 of the lateral line, faint; no caudal spot; a broad silvery lateral line. Some 

 metallic reflections. 



The specimen from the Essequibo 2488C. is deeper and has a narrower 

 second suborbital than the type. 



17. Moenkhausia shideleri, Eigenmann. 

 Plate 12, fig. 1. 



Moenkhausia shideleri Eigenmann, Annals Carnegie mug., 1909, 6, p. 15 (Bartica); Rept. Princeton univ. 

 exped. Patagonia, 1910, 3, p. 438; Mem. Carnegie mus., 1912, 6, p. 325, pi. 47, fig. 4. 



Habitat. — Essequibo River. 



Specimens examined. 



