FAMILY VI. CHARACINID^. 87 



In form this species is very variable, usually the deeper specimens 

 are more compressed than the more elongate ones. The darker speci- 

 mens are from Refugio and Motzorongo, the lighter from San Juan 

 Evangelista. The former were taken in a shady stream, the latter 

 on the edge of a sand-bar. This species is very abundant in the 

 lower portions of all streams examined by me south of Vera Cruz. 



36. Hemigrammus Gill. 



Hemigrammus Gill, Ann. N.Y. Lye. Nat. Hist., 1858,420. (Type, 

 Hemigrammus unilineatus Gill.) 



Body elongate, much compressed; belly before ventrals rounded; 

 head moderate; snout pointed; teeth in both jaws uniserial, pointed, 

 with one to three cusps ; teeth on maxillary 0-5 ; gill membranes not 

 connected, free from the isthmus; gill rakers long and slender, nu- 

 merous; lateral line incomplete. 



82. Hemigrammus compressus sp. nov. 



Type, No. 4641, F. C. M., i^i inches in length; El Hule, Oaxaca. 

 Basin of the Rio Papaloapam. (El Hule; Obispo.) 



FIG. 25. HEMIGRAMMUS COMPRESSUS Meek. 



Head z^A', depth 2^; D. u; A. 25 or 27; scales 45 to 48. Body 

 deep, much compressed; ventral region rounded before and behind 

 ventrals; mouth moderate; maxillary slender, its tip reaching vertical 

 from pupil, its length 2% in head; teeth in jaws in one series, con- 

 ical; snout short, its length slightly more than y z diameter of eye; 

 dorsal fin high, its longest ray slightly more than length of head, 

 its base i^ in head; origin of dorsal fin -midway between base 

 of caudal fin and anterior margin of eye; pectorals i^ in the head, 

 their tips reaching slightly past base of ventrals ; ventral fins slightly 

 shorter than pectorals; caudal peduncle very slender, its least depth 



