RODENTIA SACCOMYINAE PEROGNATHUS FLAVUS. 



423 



Skin mounted, from alcohol. 



Measurement. 



Nose to eye _.. 



ear 



occiput 



root of tail 



Tail, from root to end of vertebrae, (tip broken). 



Ears, height posteriorly 



internally above notch _. . . 



width . 



Arm, longest claw 



Leg, hind foot from heel to end of claws 



longest claw 



Skull, length 



width . . 



Inches. 



.46 



.92 

 1.08 

 3.00 

 2.67+ 



.25 



.25 



.21 



.14 



.80 



.12 



.98 



.50 



I unhesitatingly referred this animal to the Perognaihus fasciatus of Maximilian, until 

 the reception and examination of specimens more nearly allied to the latter. On a careful 

 comparison, however, I find that the differences are sufficient to warrant a specific separation. 

 The ears are much smaller scarcely half the size although distinctly lobed ; the feet and tail 

 perhaps longer in proportion. The upper parts are much darker; the sides lack the conspicuous 

 pale stripe. The helly hairs are plumbeous at the base, instead of pure white ; and the dark colors 

 of the back extend on the outside of the fore leg to the wrist, instead of being pure white. 



The skull, though about the size of that figured by Maximilian, is much, more mature, the 

 tubercles having disappeared entirely. 



List of specimens. 



PEROGNATHUS FLAVUS, Baird. 



Perognaihus jlavus, BAIRD, Pr. A. N. Sc. Phila. VII, April, 1855, 332. 



Sp. CH. Considerably less than the common mouse. Tail equal to or less than the head and body, scarcely different in 

 color above and below. Hind feet short. Above, yellowish buff, with dusky tips to some of the hairs; clearer on the sides; 

 Beneath, snowy white to the roots of the hairs. Fore leg white to the shoulders. Hairs on the back plumbeous only on their 

 basal half. 



This species is almost as diminutive as the P. parvus of Peale, although different in color 

 and proportions. The ears are moderately large ; the third claw of the hand longest ; the 

 fourth scarcely shorter ; the second reaching to the middle of the third ; the fifth extending 



