146 GLIRES. 
4. Hesperomys aureolus. 
Mus (Calomys) aureolus, Audubon & Bachman, Journ. Ac. Philad. vi. p. 8302 (1842, descr. orig.)’. 
Hesperomys (Vesperomys) aureolus, Coues, Proc. Ac. Philad. 1874, p. 180°; Mon. N.-Am. Rodent. 
p- 91’. 
Hesperomys nuttalli, Baird, Mamm. N. Am. p. 467 (nec Harlan?*)’. 
? Hesperomys fulvescens, de Saussure, Rev. et Mag. Zool. 1860, p. 102 (descr. orig.)’. 
Hab. Nort America, from South Carolina southwards*\—Mexico (de Saussure? ; 
Sallé, Mus. Brit.). 
I have very little hesitation in identifying M. de Saussure’s Hesperomys fulvescens 
with the Golden Mouse of the Southern United States. In his original description it 
is remarked that “pour la couleur elle se rapproche beaucoup de lH. nuttalli, Harl., 
mais elle a la queue plus longue, ses oreilles ne sont pas ferrugineuses et la couleur du 
poil parait étre un peu plus foncée”*. In the British Museum there are two Mexican 
Mice, collected by Sallé, which agree very well with M. de Saussure’s description, but 
are larger, and have the tail, though still long, proportionally shorter, while their 
ears are concolorous with the back, exactly as in H. aureolus. Dr. Coues’s table of | 
measurements of a series of the latter species shows a considerable variability in pro- 
portions, though the average length of tail is decidedly shorter than in the Mexican 
examples under consideration®. Nevertheless, when we consider the intermediate 
specimens and remember the immense extent to which other American Mice have 
been shown to vary in this respect, we must hesitate to found specific distinction 
on such a character, and better characters must, I think, be pointed out before 
H. fulvescens can be recognized as more than a long-tailed race of H. awreolus. 
5. Hesperomys californicus. 
Mus californicus, Gambel, Proc. Ac. Philad. 1848, p. 78 (descr. orig.)’. 
Hesperomys (Vesperomys) californicus, Coues, Proc. Ac. Philad. 1874, p. 180°; Mon. N.-Am. Rodent. 
p- 98°. 
Hab. Norra America, California !*.—Mexico, Tehuantepec (Boucard, Mus. Brit.). 
As Dr. Coues remarks, this large long-eared Mouse has much the appearance of a 
half-grown Neotoma. First discovered by Gambel at Monterey, its range seems to 
extend southwards to Tehuantepec; for a specimen obtained by the British Museum 
from that locality, through M. Boucard, only differs from Californian examples in 
the same collection in being rather paler and more ashy in colour. All these speci- 
mens appear to be larger than those examined by Dr. Coues, giving an average length 
* Although Harlan’s description of his Arvicola nuttalli (Am. Monthly Journ. 1832, p. 446) agrees with 
this species, it is also applicable to a rufous specimen of H. leucopus; I have therefore followed Mr. Allen 
(Bull. Mus. Comp. Zool. ii. p. 180) and Dr. Coues in retaining Audubon and Bachman’s name. 
