xlii AMERICAN FISHES. 
Europe become prominent. The Gadids are represented by the Burbot, or 
Losh (Lota Jota); and of the Dalliids, in northern Alaska there is a single 
species, named Black-fish by some (Dad/ia pectoralis), which is an important 
article of food to the natives. 
Thence going southward and eastward, a greater proportion of the special 
American types is found, but still so few in a renowned section of the east 
that it has heen designated as “ the zodlogical island of New England.” 
Stull proceeding southward, a richer fauna becomes visible, characteristic 
American types (Catostomids and Centrarchids) appear in numerous repre- 
sentatives, and some special genera of Centrarchids (Centrarchus, Asanthar- 
chus, Enneacanthus, and Mesogonistius) mark a large section as a special 
subregion—the Austroriparian. 
Florida has been isolated as another distinct subregion by American 
zodgeographers, but there are no fresh-water fishes or groups of fishes which 
corroborate such an isolation. The fishes are simply outliers of the 
Austroriparian fauna. 
The southwestern section, of which Texas forms the largest portion, is 
enriched by an overflow from the Mississippi fauna in the form of pure 
species of that basin, and slight variants developed as species. The dis- 
tinct species, however, are so few that eminent ichthyologists (Jordan and 
Gilbert) were compelled to the conclusion that “the fauna of any Texan 
river is much less rich than of any stream of similar size and character 
connected with the basin of the Mississippi;” and that “the fish fauna of 
Texas differs from that of the Lower Mississippi Valley mainly by its 
deficiencies. Texas does not properly constitute a distinct faunal region.” 
But in the lower portion of the Rio Grande system a most interesting 
assemblage is found. Therein occur representatives of two families exceed- 
ingly rich in tropical species; they are a fish like a sunfish (Heros cyano- 
- guttatus), but with single nostrils and an interrupted lateral line, and a 
shiner-like fish (Zétragonopterus argenteus), but differing very much from 
Shiners by having broad notched and compressed teeth in the jaws. The 
Heros is a member of the great family of Cichlids, and the Zé¢ragonopterus 
belongs to the important family of Characinids. 
Hastening now to the country to the north, we reach a region where the 
streams have become impoverished and the characteristic American types 
greatly reduced. Catostomids, nevertheless, remain and are represented 
by considerable numbers. They and Cyprinids, indeed, are the chief and 
in many streams almost the only representatives of the class. In the high- 
lands and mountains, however, Trouts and Whitefishes appear. 
