GEOMYS. 159 
The two species of Geomys found within our limits may be easily recognized by the 
following striking characters :— 
1. G.mexicanus. Upper incisors with a single median groove ; feet and tail hairy; 
fur soft and shining. Brownish or reddish grey above, paler beneath; length 
of head and body 10" to 11”, of tail 3”. 
2. G. hispidus. Upper incisors with one groove on the inner half of the tooth ; 
feet and tail nearly naked ; fur stiff and coarse. Dull chocolate-brown above, 
paler beneath ; length of head and body 12", of tail 3". 
The only other species in which the incisors have only one groove is G. castanops 
(Baird) of Texas and New Mexico, a much smaller animal, of a pale yellow-brown 
colour, passing into chestnut on the head. 
1. Geomys mexicanus. 
Ascomys mexicanus, Lichtenstein, Abh. Ak. Berlin, 1827, p. 118 (1830, descr. orig.)*; Charlesworth, 
P. Z.S. 1841, p. 60°. . 
Geomys mexicanus, Baird, Mamm. N. Am. p. 387°; Coues, Rep. Powell’s Expl. Colorado River, 
p. 2364; Proc. Ac. Philad. 1875, p. 183°; Mon. N.-Am. Rodent. p. 617°. 
Tucan seu Talpa Indica, Hernandez, Quad. Nov. Hisp. fol. 7, cap. xxiv. 
Tuca, Tuza, of Mexicans. 
Hab. Mexico (Uhde, Deppe, Mus. Berol.1; Liebmann, Mus. Hafn.; Geale, Mus. Brit.), 
Jalapa (de Oca, U.S. Nat. Mus.°). . 
There can be hardly a doubt that the Mexican Pocket-Gopher is the Tucan of 
Hernandez, and consequently the earliest-known species of the family, though it was 
first systematically named by Lichtenstein in 1830*. Little is known of its exact 
distribution in Mexico, but it appears to inhabit the central highlands; in some places 
it occurs along with the next species, specimens of both having been sent’ by de Oca to 
the Smithsonian Institution from Jalapa®. Dr. Coues quotes Berlandier’s unpublished 
manuscripts to the effect that G. mexicanus is found in the cold and temperate regions 
of New Spain®; and Mr. Charlesworth also met with it on the central tableland. The 
latter observer states that the cheek-pouches “are used for the purpose of conveying 
the soil from its subterranean retreats to the surface of the ground, where the mould 
is deposited in heaps similar in appearance to those formed by the common Mole”? 
The British Museum possesses two examples of melanism in this animal; these speci- 
mens, which are without exact localities, are of a very dark glossy brown, but retain 
irregular patches of their normal colour. 
2. Geomys hispidus. 
Ascomys mexicanus, Eydoux & Gervais, Mag. de Zool. 1836, art. i. p. 23, t. xxi. figg. 5 & 6"; Voy. 
de la ‘ Favorite,’ v. Mamm. p. 23, t. viii. figg. 5 & 6 (nec Lichtenstein)’. 
