GILL] NOTEWORTHY EXTRA-EUROPEAN CYPRINIDS 321 
is the average length. It is, according to Jordan and Evermann, an 
inhabitant of the “ streams of the Coast Range about San Francisco 
and Monterey, locally common as far ds Clear dhake:>° itis 
caught to some extent for the markets. 
Fic. 77.—Lavinia exilicauda. After Girard. 
MEXICAN CYPRINIDS 
Cyprinids extend far down into Mexico in the streams of the 
tableland, but in diminishing numbers southwards, and are prac- 
tically absent from the streams of the lowlands south of the Rio 
Grande valley. Altogether, about a half hundred (48) species occur 
in temperate Mexico, of which nearly half (23) are confined to the 
country and the rest (25) are common to it and southwestern United 
States. Two score species (40) occur in the valley of the Rio 
Grande and five in the Colorado river system. Five of the genera 
(Xystrosus, Stypodon, Falcula, Aztecula and Evarra) are restricted 
to Mexico, but are monotypic or represented by only two (Evarra) 
or three species (Aztecula). Further details may be found in Seth 
Meek’s monograph on “The Fresh-water Fishes of Mexico” 
(1904). 
NorTHERN ASIATIC CYPRINIDS 
The cyprinoid fauna of northern Asia is simply an extension of 
the European fauna eastward or, more properly, there is a great 
Eurasiatic realm, extending from the Pacific to the Atlantic ocean 
and from the Himalaya mountains and isothermal regions north- 
wards, which has a common fish fauna as well as continuous mammal 
and bird faunas. Many genera extend from one extreme to the 
other; for instance, Leuciscus and Phoxinus, the daces and min- 
nows, are as prominent in Japan as in Britain. 
