TROPICAL AMERICA. — MEXICO. Fa: 
we may gather from tne above facts, that Mexico ex- 
hibits nearly as great a variety in her animal produc- 
tions as she does in her vegetable. Both may be traced 
to the same cause, — the astonishing variety of climates 
concentrated in this isthmus; where the traveller can 
pass, in the space of three days, from the regions of 
perpetual snow, to the burning sands of Vera Cruz. 
Between these two extremes of heat and cold are stu- 
pendous ridges or platforms, at different elevations, of 
table lands ; as if nature, within a single degree of lati- 
tude, intended to represent the climate, the animals, 
and the vegetables of every region in the New World. 
(101.) Aquatic birds are generally more nume- 
rous in cold than in warm latitudes ; yet Mexico 
is a remarkable and almost a solitary exception. All 
travellers agree in stating, that the lakes and marshes 
on the table land are frequented by innumerable water- 
fowl; their numbers, in fact, are so immense, that 
they are killed by batteries placed in a double file, 
and many hundreds are brought down at a single 
discharge.* Yet among all those which have been 
sent to England, we only discovered two new bit- 
terns, the Mexican and the lineated species ; the rest 
were of ducks and waders, well known in the United 
States, and nearly all inhabiting the Arctic regions. It 
would thus appear that the freshwater lakes of the 
isthmus form the southern barrier of all these migra- 
tory tribes, no less than of the insectivorous summer 
visiters of the United States ; since we are, at present, 
unacquainted with a single instance of a natatorial bird 
of North America having been detected on the Terra 
Firma. Some fewof the small sandpipers may, however, 
occasionally pass to the south of the equinoctial line. 
(102.) The only Mexican reptile deserving particu~ 
lar notice, is the Phyllhydrus pisciformis Br. (the 
Axolotl of Humboldt), allied to the Siren of Carolina. 
It seems to abound in the lakes near the city of 
Mexico, and is much esteemed as an article of food. 
* Ward’s Mexico. 
F A 
