MAMMALS. 



41 



We had, however, no opportunity of observing any of that celebrated, almost miraculous, regularity and ingemiity with which, 

 accordino to general belief, the dens and dams of the beaver are constructed. 



Like the aerial nest of the Colorado tree rat or the amphibiously placed stronghold of the muskrat, the beaver's dwelling-p^ace 

 forms also a chaotic heap of drift wood, rush, aud mud. 



lu thitse nests which have come ua:!er our e^es, only one hole communicating with the out and inside could be observed. 

 Whether there are more, aud eepecitlly sub-fluuatile openings. I nm nut nhle to R^y, though I diiubt it, ar cording to wh.it I have 

 seen of beaver life. Ofthnt celebrated iugenuity and those architectural efl^rts of the beavor I could nt»t learu any panlcuLirs. 

 All the skll! exhibited iu erecting and locating rho^e hutH prove but a certain am tutit af iudtinct, of which many other m unmals 

 possess a similar share, and in which especially birds and inpecti' are far ahead. 



The most elevated point on our boundary line where beaver life came to our knowledge is the Guadaloupe cafSon, (Sierra 

 Madre,) about 5, 000 feet above salt water. The lowest beaver habitation was Feen by (iur:?elveet» about 30 miles above the mouth 

 of the Colorado, where the last timber gives way to those unbounded cane-brakes and salt marshes which border the head of the 

 Californian Gulf. 



39. GEOMYS CLAKKII, Baird, (p. 383.) Pecos Gopher. 



This species thus far has only heeu found near Presidio del Norte and on the Pecos river, 

 where several specimens were obtained. 



6. Presidio del Norte. Major W. H. Emory. Skin. J. H. Clark. 



40, THOMOMYS UMBRINUS, Baird, (p,399.)—Sonora Gopher. 



If I am correct in the identification, this species was first described from a specimen collected 

 at ^* Cadadaiguias, Louisiana/' a locality of which I can at the present day find no trace. It 

 appears to be quite abundant in New Mexico and Sonora, although its precise range is not yefc 

 well ascertained. 



154. Fort Webster. J. H. Clark. Skin. J. II. Clark.— 149, Santa Cruz, Sonora. Skin. 

 J. H. Clark. — 1036. Espia, Sonora. Skin. Dr. Kennerly. — ?1331. Santa Isabel, Califor- 

 nia. November 26, 1854. Skin. A. Schott. 



"Though traces of this animal may be often eeen in t^ie allavlal soil of the mountain vallejs in northern Mexioo, it is very 

 inconspicuous itaelf, being n'Jtturnal. It seldom exposes the whole of its body above ground in daylight. On coming to tho 

 surface, if the grass is sufficiently n'^ar to be reached, it seizes a pprijr and drags it within the entrance, and with it^ fore feet 

 packs it away in its pouches ; when this operation is completed, the opening is filiid up wiili loose earth, which ha« been 

 aptly described by suggesting its resemblance to the ** emptied contents of a Jlower-pot." If thjre is no grass near its opening, 



it will sometimes come entirely out, when it can be easily bewildered and captured. The surface gives way tinder the foot where 

 ^his pouched rat has bfen at work ; it is not the species, however, that bufrows so extensively in the prairie and piles up tlio 



large hollow mounds, the cause of many an inward curse to the inexperienced traveller '" — (J. H. Clark.) 



*' This animal had its hole on a grassy spot on the Lank of the Corralitas river. For several successive mornings before wun- 

 rise it was o' served to ciime" cautiously out to gather grass and roots, and carry tijcm into his den, never, however, vtniuring 

 more than a few feet from llie entrance. It seemed always to be une:isy and apprehensive of danger, and at the Mighest noiso 

 or motion en our part it immediate y disappeared, after the lappc of some time returning, first protruding Its head and iccon- 

 noitering. When it was killed its pouches were filled with grass, but the manner in which it was put there could not be seen. 

 The hole in which it lived was perfectly smooth, and did not go straight down, but inclined considerably, and api arently did not 

 extend far beneath the surface. Near by was a pile of dirt which had probably been removed from it." — (Dr. Kennerly.) 



41. THOMOMYS FULVUS, Baird, (p. 402.) 



This species was first obtained by Dr. AVoodhouse in the San Francisco mountains of New 

 Mexico, and appears to be confined to the regions west of the Rocky mountains. 

 1330. Fort Yuma, California. January 2, 1855. A. Schott. 



g m 



These 



