MAMMALS OF THE MEXICAN BOUNDABY, 



115 



of the pitaya cactus (Oereus thurieri), which to the westward 

 become a conspicuous feature. Large game was abundant in these 

 mountains. General collections of unusual interest were made here 

 by Mr. Holzner and the author from December 29, 1893, to January 

 8, 1894. The winter season was unfavorable for collecting reptiles, 

 Ufa stanshuriana being, as usual, the only lizard common at that time 

 of the year. 

 Flora of Poso de Luis. — The trees are : 



Salix rdgra Marshall. 

 Populus fremontii Watson. 

 Acacia greggii Gray. 

 Prosopis glandulosa Torrey. 

 Parlcinsonia microphylla Torrey. 

 Cercidium torreyanum (Watson) Sar- 

 gent. 



Olneya tesota Gray. 

 Opuntia fulgida Engelmann. 

 Opuntia versicolor Engelmann. 

 Opuntia spinosior (Engelmann) 



mey. 

 Gereus giganteus Engelmann. 

 Gereus thurieri Engelmann. 



Tou- 



Other conspicuous plants are of the genera Ephedra, Yucca, Dasy- 

 lirion. Agave, Amaranthus, Atriplex, Fouquieria, Covillea, Simmond- 

 sia, Rhus, Zizyphus, Cactus, Echinocereus, Echinocactus, Opuntia, 

 Datura, Bduvardia, Gucurhita, Xanthium, and Baccharis (several 

 species, including B. emoryi). 



Station No. 53. — Nariz Temporal, Sonora, Mexico. Station about 

 10.5 kilometers (6.5 miles) south of Monument No, 159, 626 kilo- 

 meters (389 miles) west of the Rio Grande, and 233 kilometers (145 

 miles) east of the Colorado River. Altitude, 500 meters (1,640 feet). 

 Our camp was at the south end of the Nariz Mountains, beside a pool 

 of surface water, at the western border of the Great Plain, which 

 stretches between the Cobota and Nariz mountains. Much of the 

 Great Plain, which is from 100 to 200 feet lower on the west than on 

 the east side, is covered with grass, though shrubs and cacti cover 

 large portions of it. The Nariz Mountains are very rocky, but sup- 

 port considerable undergrowth, especially near the base, which is also 

 wooded with pitaya cactus, Sonoran ironwood {Olneya tesota), 

 palo verde, and acacia. Along the laguna at the foot of the Nariz 

 Mountains is a heavy growth of mesquite, about 15 feet in height. 

 A very superficial examination of this interesting locality was made 

 by Mr. Holzner and myself on January 8 and 9, 1894, when a few 

 specimens were collected. Major Emory had taken the horned toad 

 {Anota modesta Girard) at this place. 



Station No. 54. — Santa Rosa Valley, at Monument No. 161, 632 

 kilometers (393 miles) west of the Rio Grande, and 343 kilometers 

 (141 miles) east of the Colorado River. Altitude, 516 meters (1,693 

 feet) . Visited by myself and Mr. Holzner January 9, 1 894. 



Station No. 55. — Sonoyta, Sonora, Mexico. The camp was at 

 the edge of a mesquite flat beside the Sonoyta River, about 3 kilo- 

 meters (2 miles) south of Monument No. 168, which is 661 kilometers 



