82 U. S. P. R. R. EXP. AND SURVEYS ROUTE TO CALIFORNIA. 



SP. CH. Size of the cat-squirrel, S cincreus. Ears large, prominent. Tail more than two-thirds as long as the body. 

 Above, mixed black, yellowish brown, and brown in indistinct mottlings ; beneath, pale yellowish brown. Sides of head and 

 neck, hoary yellowish, more or less lined with black, a more distinct stripe of the same, from behind the ears on each side, 

 extending above the shoulders to the middle of the body. Ears black on their inner face. Dorsal space between the stripes 

 scarcely darker than the rest of the back. Length, 9 to 11 inches; tail, with hairs, 7 to 9. Hind feet, 2 to 2.20 inches. 



Specimens (A. and B.) were collected at the Tejon Pass, California. 



SPERMOPHILUS HARRISII, Aud. & Bach .Harris Squirrel. 



Spermophilus harrisii, AUD. & BACH. N. Am. Quad. Ill, 1854, 267; pi. cliv, fig. 1. BAIRD, Gen. Rep. Mammals, 1857, 313. 



Size rather less than that of Tamias striatus. Tail vertebrae about half the length of the body. Ears short, pointed. Soles 

 hairy. Above, finely grizzled grayish, or whitish brown and black; under parts, and a stripe on each side, (without any black 

 or dusky border,) whitish. Tail with one black and one light line, within the marginal whitish, black in the centre; uniform 

 whitish beneath. Length, 5 inches ; tail, with hairs, about 3. Hind foot, 1.45. 



A specimen (No. 3) was collected in the Mohave Desert. 



THOMOMYS BULBIVORUS, B a i r d .California Gopher. 



? Diplostoma bulbivorum, RICH. F. B. Am. I, 1829,206; pi. xviii, B. (marked Diplostoma douglassi.) IB. Zool. of 



Blossom, 1839, 13. 

 Thomomys lulbivorus, BAIRD, Gen Rep. Mammals, 1857, 389. 



SP. CH. Cheek pouches large, completely furred inside, white to their very margin, which is dark brown, forming a very 

 strong contrast. Tail from one-third to less than one-half the length of body; slender at base. Upper incisors quite convex 

 transversely; groove obsolete. Hands small; claws very slender and delicate, nearly straight ; middle claw 4 J lines, its under 

 surface occupying about two-sixths the whole hand, its finger barely shorter than this ; claw of thumb extending over two-fifths 

 of whole hand. 



Color. Reddish chestnut brown above- and on sides, finely lined everywhere by dusky tips to the hairs, without any uniform 

 dark wash on the back. Beneath paler. Tail grayish white, except a short line of dusky along the base above. Chin dusky ; 

 its extremity white. 



Specimens collected at Tejon valley. (2.) 



DIPODOMYS PHILLIPPII, Gray .Kangaroo Eat. 



BAIRD, Gen. Rep. Mammals, 1857, 412. 



Specimens of this species were collected at Posa creek. 



PEROGNATHUS PARVUS, L e c o n t e . 



Cricctodipus parvus, PLALE, Mamm. and Birds, U. S. Ex. Ex. 1818, 53. 

 1 crognathus parvus, BAIRD, Gen. Eep. Mammals, 1857, 425. 



SP. CH Smallest known species of American rodent ? Above, buff, mixed with dusky ; beneath, white ; entire fore leg white 

 Tail rather longer than the body. Hind foot from heel nearly as long as the head. 



A specimen was collected on King s river, California. (6.) 



HESPEROMYS GAMBELII, B a i r d .California Mouse. 



BAIRD, Gen. Eep. Mammals, 1857, 4fi4. 



The specimens of this species collected at Posa creek differed in some respects from those 

 generally procured in northern California, in heing smaller and darker colored. They are, 

 however, possibly immature, which would account for the difference. (Nos. 4, 5, and 7.) 



