694 » Hans: GApow, 
drawing attention to the defective state of our faunistic knowledge 
of the country, future naturalists may be induced to amend it. 
It may seem unwarranted to expect conclusive results from so 
small a number as 94 species. However as they were not selected 
but simply happened to be those about the altitudinal range of 
which I could get satisfactory data, the statistical curves which 
they yield, appear so unbroken and free from vagaries that this cannot 
well be merely accidental, but must be due to the whole list being 
fairly representative. Only in one point they must be wrong. The 
number of exclusively Hot-country species, chiefly “Southerners” is 
relatively much greater than represented (cf. especially Diagram III, 
and also p. 229, with diagram in: Proc. zool. Soc. London 1905) and 
it is these Lowland species about the range of which we know least. 
Lastly many of them seem to be restricted to the South Eastern part 
of tropical Mexico, at the Isthmus, therefore hardly representative. 
It cannot be expected that all the results discussed in this 
paper are more than tentative. Some, I trust, will be contested, 
which may mean progress!), as they can be contested only upon 
1) The following statement (in: Proc. zool. Soc. London, 1905, 
p. 196) has produced a most valuable result, thanks to Prof. P. P. CALVERT. 
‚Altitude is supposed to be all-sufficient; but this is a great mistake, 
since it conveys nothing without further information. For instance, 2000 feet 
on the Atlantic slope means typical tropical hot-country vegetation, while 
on the Pacific side (e. g. Oaxaca and Guerrero) the same elevation implies 
pine — and oak forests, with a character devoid of tropical fauna and 
flora . . . Chilpancingo 4100 ft. in Guerrero has a much cooler climate, 
with nothing tropical about its vegetation, than Oaxaca, 5060 feet, or even 
Orizaba at 4027 feet, which is in many respects subtropical.” The above 
has been taken by CALVERT as an ‘“assertion of the existence of a much 
cooler climate on the Pacific, than on the Atlantic side of Mexico at 
almost the same elevation”. Although nothing was further from my 
mind than such a sweeping assertion, I own to having expressed my meaning 
badly, namely that the same elevation may produce different effects on the 
two slopes;; further information about probable factors, the different amount of 
drainfall was mentioned on p. 237— 239. The term ‘“tropical” should not 
have been used in two senses, or in such a loose sense as synonymous 
with luxuriant, in the case of the Atlantic slope. Tropical vegetation is, 
in Mexico as elswhere, luxuriant (hot and moist climate) or xerophile (hot 
and dry). At least I should have said that on the Paeific slope the same 
elevation implies [sometimes] pine and oak forests, with a character 
devoid of the luxuriant character of the Atlantic slope. The want of 
clearness was exaggerated by passing next on to differences of temperature at 
