eigenmann: the cheirodontin^. 73 



caudal and number seventeen to twenty-seven, all or only half of which may pro- 

 trude in the male. The maxillary has but one tooth. 



Head 4.5-4.66; depth 2.4-3; D. 11, very rarely 12; A. 17-24; scales ¥, ¥, 

 ^, %-,^, in those examined; seven to twelve scales with pores; eye 2.5-3, about 

 equal to interorbital ; depth of caudal peduncle 1-1.5 in its length. 



Compressed, dorsal and ventral profiles equally arched; preventral area 

 flattened, with a median series of about thirteen scales; predorsal area rounded, 

 with thirteen scales; frontal fontanel from half to one-third as long as the parietal; 

 a broad naked area behind the third suborbital, sometimes extending forward a 

 little at the angle of the preopercle, postorbital not half as wide as the naked 

 area behind it; mouth small, maxillary little, if any, longer than half the eye, 

 shortest in specimens from Cacequj^ and Maldonado, in which its free margin is 

 more convex. Premaxillary with four or five teeth (six in a few premaxillaries) ; 

 maxillary uniformly with a single tooth (except in one maxillary, which in addition 

 has a minute tooth); five, six, or seven graduate teeth in mandible, the teeth 

 five- to seven-pointed, the base narrower than the tip. GiU-rakers 7 + 12, to 

 9 + 13, short, the longest not quite a third as long as the eye. 



Origin of the dorsal equidistant from tip of snout and base of mid-caudal rays. 



Fig. 25. Cheirodon monodon Cope, a and b, premajdllary and maxillary with their teeth. 



Adipose fin well-developed. Origin of anal about equidistant from snout with 

 last dorsal ray. Pectorals reaching ventrals, the ventrals not quite to the anal, 

 the fourth or fifth to the eighth to fourteenth anal rays of the male with hooks; 

 the ventrals in adult males also with hooks; seventeen or more interhsemals on 

 caudal peduncle, those of male contiguous, with broad lateral processes, especially 

 the anterior ones, their spines projecting from near base of last anal ray. 



Scales thin, regularly imbricate, with few to many diverging radial striae; 

 caudal naked; anal with a few scales in a single series at base of anterior rays. 



A silvery lateral stripe; chromatophores variously developed, some speci- 

 mens from Cacequy are almost free from pigment, except a faint caudal spot; 

 in others the pigment is well-developed, the specimens appearing quite dark, the 

 caudal spot being well defined or more diffuse in outline, not extending upon mid- 



