2 g COLUMBIA POUCHED-RAT. 
as California to the south, and the Russian Possessions in the opposite 
direction. We have seen some mutilated specimens, which appeared to 
be of this species, obtained by a party in the western portion of New 
Mexico, but so dilapidated were they, that it was impossible to decide 
positively as to their identity, and they may have been skins of another 
species, called by Dr. Richardson Geomys Umbrinus, which he was informed 
came from the southwestern part of Louisiana. 
GENERAL REMARKS. 
Mr. Douglas informed Dr. Richardson “ that the outside of the pouches 
was cold to the touch, even when the animal was alive, and that on the 
inside they were lined with small, orbicular, indurated glands, more 
numerous near the opening into the mouth. When full, the pouches had 
an oblong form, and when empty they were corrugated or retracted to one 
third of their length.” 
We presume this information is correct, although the mistake made by 
supposing the “ inverted” pouches of some species of Pseudostoma, to be in 
their natural position (see the genus dvplostoma of Raffinesque, adopted by 
Richardson), leads us to look with caution on any accounts of the pouches 
of our Sand-Rats from this source. 
