MAMMALS. 



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35, SPERMOPHILUS MEXICANUS, Wagner, (p. 319.)— Mexican Ground Squirrel. 



This well kown spermophile is found probably tbrougbout Mexico, altliough the Rio Grande 

 appears to be about its northern limit. It is found as far west as the Pecos, and even at El 

 Paso, where, however, it begins to be replaced by S. spilosoma^ which in turn extends to the 

 Gulf of California. 



518. Pesquiera Grande, Mex. May, 1853. Lt. D. N. Couch, U. S, A. 203.-2498. 

 Matamoras, Mex. May, 1853. Lt. D. N. Couch, U. S. A.— 352. Brownsville, Tex. Feb., 

 1853. Lt, D. N. Couch, U. S, A.— 140. Eagle Pass, Tex. 1852. A. Schott. 



" This species was found in greatest numbers in the valley of the lower Rio Grande. It lives in the ground, and its burrow 

 is always made with reference to the protection aflbrded by a thorny brush or cacti against the attacks of the coyote and otlier 

 enemies. If the entrance happens to be in an exposed place, it is sometimes fortified by tliurny pieces of the mLs^uito and cacti. 

 Though somewhat companionable, each, as a rule, seems to have its own house. Like other mammals, it is most above ground in 

 the morning and evening in search of food ; yet it is apparently the least affected by the heat of the midday sun. It is omnivorous . 

 Its bed is a globular mass, lined with soft material, and has but one entrance-" — (J. II. Clark.) 



36. SPERMOPUILUS SPILOSOMA, Bennett (p. 321.)— Sonora Ground Squirrel. 



This species was first described by Bennett from a specimen obtained in western Mexico, It 

 occurs abundantly from the Gulf of California as far east as El Paso, and even northward to 

 Fort Stanton. 



290. Chihuahua city. 1853. John Potts. — 1042. Janos, Sonora. April, 1855. Dr.Kennerly. 



141. 9 . El Paso. 1852. J. H, Clark. 



"This species was quite common on the prairies around Jano3. It lived sometimes among the rocks, but more oflen had its 

 bed in piles of dirt heaped around the base of some bush. These piles were elevated several feet above the surrounding ground, 

 and were entered by three, four, or more apertures near its summit. They were exceedingly shy, and a specimen was pro- 

 cured with difficulty," — (Dr. Kennerly.) 



37. OYNOMYS LUDOYICIANUS, Baird (p. 331.)— Prairie Dog. 



The well known prairie Jog is an inhabitant of the central portions of the United States^ from 

 the Upper Missouri region to the Eio Grande. It has not yet been found west of the Rocky 

 mountains, unless a young animal, possibly of this species, collected by Dr. Kennerly between 

 Janos and San Luis Spring, may be considered as indicating this fact. 



1054. DeviPs river, Tex. Dr. C. B. Kennerly. — 1035. O. San Luis Spring* April, 1855. 

 J. H. Clark.— 161. Limpio Mts. J. H. Clark.— 108. San Antonio to El Paso. J. II. Clark. 



" This animal is well known under the name of * prairie do^/ and as almost the only inhabitant of the high dry prairie land, 

 destitute of every form of vegetation except graaa. The purslcy {Portulacca) is a favorite foad ; in the most populous parts of 

 their towns, after having eaten up the grass to the very roots, they migrate to a more verdant spot. In extensive towns of old 

 standing there is sometimes scarcely a sprig of grass to be seen for miles. They prefer the deprasstons or hollows in the 

 prairies, partly because of the greater amount of vegetation in such places, but also because of the reservoirs of water that are 

 probably collected here. When the water has wholly evaporated, or sunk below their reach, as sometimes must bo the case, 

 the succulent roots supply its place. Whether the result of instinct or a rational deduction, their habit certainly comes under 

 the motto of * early to bed and early to rise ;" for little is seen or heard of them after sunset ; and before sunrise they are 

 n in great numbers and all sizes, feeding, chasing each other, or sitting on their liaunclies ; they frequently a«iume this latter 

 position when approached. As the sun heightens and it l>ecomes hot they disappear in their burrows, ti I, in the heat of the day, 

 there is scarcely one to be seen. Wheu it rains they come out in great numbers, pile dirt around the entrance to their holes, 

 which are sometimes completely covered over, presenting the appearance of a dutch oven in minature. In closing up their 

 burrows, they mix grass with the mud and work from the inside after it is nearly completed. There is no doubt that this is 

 done with the object of securing themselves against the water that may collect or run through the depressions in the prairie 

 \vhich they inhabit. oi.cc witt.ewcd, '.ear Preadio del Noilc, the 'drowuii g out * cf a fmall town by a sudden and heavy 



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