FRESH- WATER FISHES OF WESTERN CUBA. 
221 
in the streams of eastern North America, and Agonostomus monticola is found in the 
fresh waters of the West Indies and Mexico. Of the remaining species only those 
of the genus Ileros belong to a strictly fresh-water family. The genus Ileros is gen- 
erally distributed in South and Central American waters, one of its members entering 
the United States. The members of the marine family of Gobiidae, are found in the 
streams and brackish water of tropical America generally, and their presence in 
Cuba is not so significant as their absence woidd be. A number of the species 
enumerated are marine, and their presence in the rivers may be looked upon as 
purely fortuitous; these are Ta/rpon atlanticus, Doryrhampkns l ineatus, Centropornus 
undecimadis , Lutianus jocu , L. griseus , Eucinostomus meeki , Gobius soporator, G. 
boleosoma , and Lophogobius cyprinoides. 
Two species, in many ways the most interesting fishes found in the region exam- 
ined, are members of the deep-sea family Erotulidse; they are the blind-fishes Stygi- 
cola dentatus and Lucifuga subterraneus. These have evidently worked their way up 
the underground streams and are now becoming readapted to the light in the upper 
courses of the streams. No other members of the family are found in fresh water 
anywhere. Atherina is a marine genus with the peculiar Cuban species as its sole 
fresh- water representative. The remaining species are all members of the Poeciliidae , , 
a family inhabiting brackish water and coastwise streams. Of the Pceciliidae. 2 
genera, Girardinus and Toxus , are peculiar to Cuba. 
The origin of the Cuban fauna is then not far to seek. Wo have, as mentioned 
above, a number of marine species, more or less regular visitors of the fresh water. 
We have species widely distributed in the brackish water and coastwise streams 
whose presence is predicable ( Gobiidae ), and wo have local modifications of families 
with a wide distribution in the brackish and fresh waters of the tropics of America 
( PoGciliidan ). We have, furthermore, local adaptations of marine species to fresh 
water (Broiulidae and Atherina). The origin of all the above is simple of explana- 
tion. The species whose presence is of greatest interest are the strictly fresh-water 
species of Lepisosteus , evidently belonging to the North American fauna, and Syvi- 
branehus and Ileros as evidently members of the South American fauna. The pres- 
ence of the eel in the fresh waters of Cuba is to be expected, inasmuch as it very 
probably breeds in the ocean near Cuba. The presence of Symbranc/ms , Ileros , and 
Lepisosteus tristcechus and Agonostoma monticola shows that the fresh-water fauna of 
Cuba has a greater affinity for that of Mexico than for that of Florida, and that these 
forms probably reached Cuba by way of Yucatan. 
