eigenmann: the cheirodontin^. 



55 



teeth, of which one or more may be conical; mandible with seven or eight tricuspid 

 and five to nine conical teeth; occasionally one of the premaxillary teeth is placed 

 a little in front of the line of the others, suggesting Hyphessohrycon; second sub- 

 orbital leaving only a narrow naked wedge behind it; postorbitals very feeble. 

 Gill-rakers 5 + 13. 



Origin of dorsal equidistant from tip of snout and base of caudal; dorsal 



Fig. 16. Megalamphodus micropterus Eigenmann. a, side of head; 6, top of head, showing frontal (/) 

 and occipital (o) fontanels; c, d, e, premaxillary, maxillary, and mandible of a specimen, 6903, C. M., greatly 

 enlarged; /, outline of entire mandible; g, portion of a maxillary; h, i, j, k, premaxillaries showing the teeth. In 

 fig. h there is at x a tooth out of hne, forming an incipient second series. 



pointed, its highest rays, second to fourth, not quite equal to the head in length; 

 caudal lobes not quite equal to the length of the head; origin of anal under middle 

 of dorsal; margin of anal truncate, the rays slightlj^ graduate, no lobe, the highest 

 ray equal to snout and eye; ventrals reaching nearly to, or a little beyond, origin of 

 anal, pectorals to beyond base of ventrals; males with hooks on the third to six- 

 teenth anal rays. 



Scales thin with a few divergent radial striic; caudal and anal naked. 



Sides (in males?) uniformly dusted, or (in females?) with a distinct humeral 

 band ; all but first and last three or four dorsal rays black ; caudal and anal margined 

 with black; ventrals and pectorals sometimes tipped with dark. 



