I40 Field ColiJmbian Museum — Zoology, Vol. VII. 



Famil}- CentropOniidjF. 



Centropomus nigrescens Giinther. 

 Caballo Blanco (15), 50 to 135 mm. 



Family Lvitiaiiidse^ 



Neomaenis argentiventris (Peters). 



One small specimen taken in fresh water. Color in life red, in 

 spirits a nearly uniform reddish-brown, lighter in ventral region. 

 Head 2.53; depth 2.53; D. x. 16; A. iii, 8; scales 50; 7 rows of 

 scales between dorsal fin and lateral line ; maxillary reaching to ante- 

 rior margin of pupil, its length 2.62 in head; mandible 1.94; snout 

 3.48; diameter of eye 3.06; interorbital 5.86; longest dorsal spine 

 2.35; second anal spine 2.23; pectoral reaching slightly past vent, 

 1.27 in head. 



Caballo Blanco (i), 70 mm. 



Family Cichlitlse. 



Cichlasoma macracanthum (Giinther). 



San Jos^ del Idolo (i), 50 mm. ; Caballo Blanco (2). 



Cichlasoma centrale Meek. 

 Caballo Blanco (i), 103 mm. 



Cichlasoma trimaculatum (Gimther). 



This sjK'cies has a deeper and more compressed body than that of 

 Cichlasoma mojarra Meek. It also has a less pointed snout, smaller 

 mouth, shorter anal base, a narrower preorbital, larger eye, higher 

 dorsal and anal fins, longer pectoral fins, and a deeper caudal peduncle. 

 The dark vertical bars on posterior half of body are also more prom- 

 inent. The following is a comparison of three specimens of nearly 

 equal size of each of these two species. 



C. trimaculatum'. Total length 171 to 200 mm. Head 2.3 to 2.6; 



