COUES ON GEOMYS AND THOMOMYS T. CLUSIUS. 263 
markings of the mouth-parts and pouches are much obscured, and the fore 
claws are fully as long as in some northern examples of talpoides. Half- 
grown specimens, as elsewhere in the family, are lead-colored, merely paler 
below. 
A melanistic specimen from Cantonment Burgwyn, New Mexico, is a 
uniform, intense, lustrous plumbago color (almott like anthracite coal), with 
white lips and pouches. 
In this form, which exhibits such variation as well as intensity of color, 
we observe more clearly than elsewhere the changes produced in the shed 
ding and renewal of the pelage. It seems to be the rule in this genus, as 
in Geomys, that the hair is cast from before backward by a regular progression. 
As already hinted, the animals appear to grow gray with age ; but, besides 
this, each annual or seasonal coat seems to lose its richness of coloration 
toward the time that it is to fall off, and the fresh coat comes out more 
heavily tinted. It results from this, in connection with the peculiar mode 
of shedding, that patchy specimens are of frequent occurrence, with a sharp 
line of demarkation between differently-colored areas (Geomys castanops is 
a notable case of this). Some examples before me are, in fact, strong 
"umbrinus" in front and very fair "bulbivorus" behind. Season, as well as 
age, doubtless influences the color of the pelage, but exactly to what extent 
I am unable to say, owing to the usual oversight of collectors in neglecting 
to date their labels. 
The geographical distribution of the species, as far as now known, is 
indicated in a preceding paragraph. The original locality given for umbrinus 
has not been checked by subsequent accounts, and is probably somewhat out 
of the way ; Texas or New Mexico being more likely the source of the type- 
specimen described by Richardson. I see no occasion to question Baird's 
identification of the species, with which the Geomys fulvus of Woodhouse is 
indisputably identical. 
THOMOMYS CLUSIUS, Coues, nov. sp. 
SP. CHAR. Smallest known species of the genus. Length (9, adult) 
about 5 inches. Feet remarkably small ; sole of hind foot 0.75 ; palm of 
hand, including longest claw, 0.65. Fore claws small, weak, little curved, the 
