42 UNITED &TATES AND MEXICAN BOUNDARY. 



"The specimen of our collection was obtained on the sandy banks of the Colorado, not far below Fort Yuma. I found it 

 slowly moving upon the drifting sand between the river thickets formed by willows, cotton trees, bacharis, and tcssaria. As it 

 did not seem to notice much my approach, I concluded that tliia animal must be weak-sighted in daylight and probably 

 nocturnal in its habits." — (A. fecholt.) 



42. DIPODOMYS OEDII, Wood house, (p. 410.)— Kangaroo Eat. 



This species was first described by Dr. Woodhouse from specimens collected at El Paso, tbe 

 same locality as that of the boundary collections. 



560. El Paso, Texas. J, H. Clark.— 1044. Mesilla valley. 1855. Dr. Kennerly.— 143. 

 Santa Cruz, Sonora. J. H. Clark. — 372. Dnrango, Mexico. Dr. T. H. Webb, 



"This species inhabits loose or sandy soil habitually, where may be fe'eenTj)iIes of dirt of an'oval "shape scattered here and 

 there each of which would fill a cart. These heaps of dirt are hollow, and liave several entrances about the base, which are mu^h 

 larger than the animal. Sometimes, after the habitation seems to be completed, the dirt is brought out^of these holes aJid 

 deposited at a distance of several yards. Their labor is done almost entirely at night, and they are but seldom seen by day- 

 light. The piles of dirt readily give way under the foot, and a mule or horse will shrink from them with as much fear as they 

 do from a rattlesnake. I could never succeed in frightening out the occupants by rur^ning sticks into the entrances or knocking 



he heaps in. Rattlesnakes are often seen in the holes, which form a constant and secure retreat for all the lizards " — (J. H. 



Clark ) 



43. DIPODOMYS AGILIS, aambel, (p. 414.) 



It is "witli some tesitation tliat I refer the 



Mr. Scliott to this species, 



as they are too young to furnish any very satisfactory indications 

 1348. Fort Yuma, California. In alcohol. A. Schott. 



44, PEROaNATHUS PENICILLATUS, Woodhouse, (p. 418.) 



1332. Colorado river. February 22, 1855. A. Schott.— 1333. Fort Yuma. A. Schott 

 Colorado desert. In alcohol, A. Schott. 



45. PEROGNATHUS HISPIDUS, Baird. (p. 421.) 



Of this species several specimens were collected at Matamoras, and it prohably extends further 

 north into Texas. 



577. Charco Escondido, and 576. Matamoras, Mex. Lt. Couch. 



w 



46. PEKOGNATHUS FLAVUS, BaUd. (p. 423.) 



This species is found (^uite abundantly throughout the west, from the lower Eio Grande to El 

 Paso, and a considerable distance westward. It also extends througli the Kocky 



mountains 



Missouri 



Majo 



In alcohol. Dr. C. B. Kennerly.— 1041. El 



Paso to Los Nogales. In alcohol. Dr. 0. B. Kennerly.— 148. El Paso. 1851. Col. 

 Graham. J. H. Clark. — 2623. Chihuahua. Dr. T. H. Webb. 



47. MUS TECTORUM, S a vi . (p. 144 1.)— White-bellied Rat ; Roof Rat. 



Of this species of rat, specimens were collected at Cadereita, New Leon, by Lt. Couch, and 

 skulls, apparently of the same species, are in the Berlandier collection from Matamoras 



1. 



f 



