122 FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. VII. 



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

 Sci., Phila., 1877, 182, 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 xvn, n to 13; A. vi 

 to viu, 7 to 9; scales 8-32-11. 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 abundant in Lake Managua 

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

 so far as known. 



Of all the species 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 tangible constant characters to define them. To 



