186 BULLETIN OF THE 
18. Neotoma floridana mexicana (Baird), Allen. Mexican Busa Rar; 
“RATA DEL CAMPO,” 
Neotoma mexicana, BAIRD, Proc. Acad. Nat. Sci. Phila., VIIL, April, 1855, 333 ; 
Mam. N. Am., 1857, 490 ; U. S. & Mex. Bound. Surv., II. Pt. 2, 1859, Mam., 
p. 54, Pl. XXIV. fig. 1, skull. 
Neotoma micropus, Barro, Proc. Acad. Nat. Sci. Phila., VII., April, 1855, 333; 
Mam. N. Am., 1857, 492; U. S. & Mex. Bound. Surv., II. Pt. 2, 1859, Mam., 
p. 44. 
Neotoma floridana, GEOFFROY, Zool. Voy. Venus, 1855, 154, Pl. XIII. — Coues, 
Mon. N. Am. Roden., 1877, 14 (partim). — Dugés, La Fraternidad, I., 1874, 82, 
PI. (animal, details of external parts, skull, and dentition). 
A series of eight specimens, two collected in October and the remainder in 
March, at San Luis Potosi, contrast so strongly in color and size with Florida 
examples of Neotoma that the Mexican form seems eminently worthy of varie- 
tal recognition. The Mexican specimens are fully one fourth smaller, the tails 
are much more thickly clothed, and the color is widely different, agreeing, 
however, in every respect with JV. mexicana, Baird, The tail is sharply bicolor, 
and the feet and the lower surface of the body are snowy white, separated from 
the mouse-brown of the back by a well-marked band of yellowish-rufous or 
golden-rust, varying in intensity in different individuals. Two specimens 
have the dorsal surface strongly ferrugineous throughout, varied of course with 
black medially, passing into strong reddish brown on the sides, thus in general 
tint strongly resembling N. ferruginea, for which they were at first mistaken. 
One is a male, the other a female, and they were taken, respectively, March 10 
and March 24. Another specimen, a female, taken March 20, presents the 
opposite extreme of paleness, being gray above, varied with black and faintly 
tinged on the sides with a pinkish hue, These examples indicate an exceedingly 
wide range of individual variation in color ; the other specimens, however, are 
variously intermediate, and form altogether a closely intergrading series. 
“These rats are sold in the markets as food for invalids whose stomachs are 
anable to retain other food ; as a cure for chronic diarrhoea and dysentery is 
believed to have few equals. The animals are split open and applied as a 
poultice to parts affected with pain. The market of San Luis Potosi is never 
without these rats. They are said to be good eating aside from their as- 
cribed medicinal virtue, They are very abundant, inhabiting the localities 
of the magueys or agaves, about the roots of which they live, probably be- 
cause the thorny nature of the plant prevents rapacious animals from bur- 
rowing after the rats, or possibly in order to feast upon the roots. They 
live in the ground, and the daily supply seen in the market of San Luis Potosi 
is obtained by digging them out of their burrows. "They are known under the 
name Rata del Campo." 
Dr. Palmer has kindly called my attention to two papers on this species in 
“La Fraternidad 7 * by Don Alfredo Dugés and Dr. Gregorio Barrocta, the 
* La Fraternidad — Periódico de la Sociedad Medica de San Luis Potosi, Tom. Los 
Entr. No. 6, Junio de 1874, pp. 82-87 y pl. 
