4 
correct, I am unable to state from my own knowledge, but in con- © 
versation with other zoologists I find that his classification i is not 
amined, that his classification is inaccurate. His Sonoran lies half 
in the Tropics and half in the Temperate 8 zone. His Transi- 
tion is a remarkably distinct life zone, shov ing less transition and 
a more distinct flora than any other life zone in his classification, 
and it corresponds to the central portion of the Temperate life 
zone, is Boreal is equally divided between the Temperate and 
the Frigid and cannot by any possibility be separated trom the 
Temperate. This will be shown conclusively by my diagrams of 
the distribution of families, genera and species. It is a generally 
accepted rule that the first publication of an idea or a name shall 
be used among scientific men-unless it shall be shown to be funda- 
mentally erroneous or inapplicable. Therefore the classification 
of Humboldt, which has never been improved upon, must take the 
Humid and Arid, and only the latter division is found in our region. 
The upper temperature limit of oes life zone is about 60°- annual 
mean and crosses our region in a very irregular line, following the 
topography from. pc Secteaeerng New Mexico, to the Salt River 
Basin, OORT ESE Junction an ingman, Arizona, thence in a 
Mogollon mountains and the Great Plateau of the San Francisco 
region in Arizona; in the latter, the upper division of the Temper- 
ate, namelv, the Frigid, is represented on the high peaks. The 
‘north of Mexico this life zone is represented by — fam- 
ilies which are found only in that zone, and by seventy- 
fam- 
ilies which also extend into other zones. The total Aone of 
a a ee 
