C. H. TYLER TOWNSEND — BIOGEOGRAPHY OE MEXICO, ETC. 
85 
from the Yucatan Plains (see Millspaugh’s. two contributions to the 
Flora of Yucatan). 
The Character oe the Ahstroriparian in the Texas and Mex- 
ican Coast Region. — There are some peculiarities in the biogeography 
of the Texas coast region that merit consideration. The Austroriparian 
would, no doubt, were the conditions of humidity and soil alike through- 
out, extend from Louisiana and eastern Texas in one broad belt covering 
the whole coast region and lowlands of Texas and northern Tamaulipas; 
finally losing itself far to the south in Mexico, running along the moun- 
tain sides just above the Tropical. But the conditions of humidity and 
soil in the Texas-Tamaulipas coast region are quite different from those 
of Louisiana; and thus we find a different state of things — the only state 
that could exist under the prevailing conditions. The Lower Sonoran 
extends east to the vicinity of San Antonio, and stretches from there 
southeasterly toward the coast, following the broad strip of coast country 
south into Tamaulipas. But in the river valleys and bottoms, where 
greater humidity and a different soil obtain, as particularly in the lower 
valleys of the Nueces and Rio Grande, the Austroriparian reappears, 
mixed moreYr less with the surrounding Lower Sonoran , and also with 
the Tropical forms to the south which come up to meet it. It thus ob- 
tains in places, like spots on the face of the Lower Sonoran. It doubtless 
becomes more continuously established farther to the south, in the moist 
regions of the mountain slopes of eastern Mexico, above the Tropical ; 
though somewhat changed in character, from accessions of Mexican 
forms and losses of others which it possessed farther north. There is a 
certain analogy between the conditions of the Austroriparian in Texas 
and Tamaulipas, and those of the Tropical on the Pacific coast of Mex- 
ico, as set forth in the remarks under the head of Isthmus of Tehuan- 
tepec. 
ERRATA IN PAPER I. 
Page 74, line 16 from top, read: parvifolius. 
Page 74, line 20 from bottom, read: angusiifolia (now known as Y. 
elata)* 
Page 74, line 18 from bottom, read: Fouquiera. 
Page 78, line 10 from bottom, read: Cook’s Peak. 
Page 80, line 2 from top, read: which lies at the northwest end of the 
Sacramentos. 
Page 81, line 14 from bottom, read: 9000 feet. 
Page 85, line 17 from bottom, read: slopes of the termination of the 
high plateau region. 
