122 Field Columbian Museum — Zoology, Vol. VII. 



Nicaragua; Lake Managua: Gill & Bransford, Proc. Acad. Nat. 

 Sci., Phila., 1877, ^^2, Lake Nicaragua. 



Heros' basilaris Gill & Bransford, 1. c. 182, Lake Nicaragua. 



Head 2.5 to 2.7; depth 1.8 to 2.3; D. xvi to xvii, 11 to 13; A. vi 

 to viii, 7 to 9; scales 8-32-1 1. Body compressed, profile slightly 

 concave at interorbital ; dorsal region elevated; mouth moderate, its 

 gape oblique; end of maxillary not reaching vertical from front of 

 orbit, its length 2.8 to 3.2 in head; mandible strong, its length 2.3 to 

 2.6 in head; preorbital broad, 3.5 to 4.8 in head; postorbital 2.2 to 

 2.4; diameter of eye 3.9 to 4.6; distance from lower margin of orbit 

 to lower edge of subopercle 2.3 to 2.8; distance from tip of snout to 

 scales on nape 1.8 to 2.0 in head; gill rakers 3+10; cheeks with five 

 rows of scales ; lower lip with margin free ; origin of dorsal fin above 

 base of pectoral, its distance from end of snout 2.2 to 2.4 in body; 

 dorsal spines increase in length rapidly to fifth spine, then gradually 

 to last spine; length of last dorsal spine 2.3 to 3.0 in head; last anal 

 spine 2.2 to 3.0 in head; base of anal fin 3.3 to 3.7 in body; middle 

 rays of soft dorsal and anal attenuated, in some of the larger specimens 

 (180 mm.) these filaments reaching nearly to end of caudal fin; pec- 

 toral fin short, its tip not reaching anal fin in some of the larger indi- 

 viduals, to.fourth anal spine in some smaller ones (100 mm.); length 

 of pectoral i.o to 1.2 in head; ventral with rays produced, length i 

 to 1.2 in head; tips of ventrals reaching third to fifth anal spine; 

 caudal peduncle deeper than long, its depth 2.5 to 2.8 in head, its 

 length 3.1 to 3.8 in head; caudal fin rounded, its middle rays slightly 

 emarginate. 



Color variable, typical color dark olivaceous; sides with 7 dark 

 bars ; usually a dark spot on 4th bar just below the lateral band ; on 

 larger individuals (180 mm.) scarcely a trace of this spot, on smaller 

 individuals (90 mm.) a spot on each bar, giving the appearance of an 

 interrupted lateral band ; a black caudal spot above lateral line ; ver- 

 tical fins plain or with a few faint dark spots. 



This species is very abundant in Lake Tiscapa, Nicaragua. The 

 above description is based on a number of individuals ranging from 

 100 to 187 mm. This species is also very abun<lant in Lake Managua 

 and Lake Nicaragua. It is the only Cichlid inhabiting Lake Tiscapa, 

 so far as known. 



Of all the s|)ecies fishes in these lakes, this one is by far the most 

 variable. I made many repeated efforts to divide this material listed 

 below in from two to a half-dozen or more species, but in all cases I 

 was unable to find any tang^ible constant characters to define them. To 



