XV1 INTRODUCTION. 
Mexico (7. e. Southern Vera Cruz, Oaxaca, Chiapas), British Honduras, and Guatemala. 
In this area 41 species occur, and to the north of it the Cichlid fauna is a very poor 
one, comprising one species from the Balsas, another from the lowland streams of 
Sinaloa and Jalisco, four from the Panuco (one of which also occurs in the Rio Soto 
Marina and the Rio Grande), and an additional species from the tributaries of the 
Rio Grande in Nuevo Leon. 
The great lakes of Nicaragua, Lakes Managua and Nicaragua, have a peculiar 
Cichlid fauna, consisting of 18 species, all but one of which are endemic. These 
include some remarkable types, such as the genera Herotilapia and Neetroplus, and 
specialized forms of the genus Cichlosoma, such as C. labiatum and C. lobochilus, with 
thick lips and large blunt teeth, C. managuense and C. dovit, with very protractile 
mouth, and C. balteatum and C. nicaraguense, with the profile of the snout nearly 
vertical. It is certainly curious that each of the sections Theraps, Archocentrus, 
Astatheros, and Parapetenia is represented in the Great Lakes of Nicaragua by its 
most specialized types. 
Nothing is known of the Cichlid fauna of Honduras, Salvador, and Nicaragua north 
and west of the Great Lakes, but it may be inferred that it is of the same general 
character as that of Guatemala and that many of the species will prove to be the 
same, seeing that Cichlosoma maculicauda of Guatemala is also found in the Rio 
Chagres. Except C. maculicauda and the two species belonging to the South-American 
genera Acara and Geophagus, only four Cichlids have been described from Costa Rica 
and Panama. These are: (1) Cichlosoma citrinellum, also found in Lake Nicaragua ; 
(2) Cichlosoma altifrons, very close to C. rostratum of Lake Nicaragua; (3) Cichlosoma 
alfari, allied to C. balteatum of Lake Nicaragua; and (4) Paraneetroplus sieboldii, 
congeneric with P. dulleri from Southern Mexico, but also near to Neetroplus 
nematopus of the Great Lakes of Nicaragua. 
The Prercip# are fresh-water fishes of North America, east of the Rocky Mountains, 
and Western Eurasia. Of nearly 100 species about 80 belong to the North-American 
genera Etheostoma, Percina, Boleosoma, &c., comprising the dwarf Perches known as 
“ darters.” Only 6 species of these extend southward to the basin of the Rio Grande 
and the rivers of Chihuahua and Durango. Fossil Percide are found in the middle 
Eocene deposits of Wyoming. 
The CENTRARCHIDH are fresh-water fishes of North America. Of about 30 species, 
which may be grouped into 8 or 9 genera, all but one, the Californian Amb/oplites 
interruptus, are found east of the Rocky Mountains. Six species extend southward to 
the Rio Grande, and one a little further, into Tamaulipas. 
