HESPEROMYS. 149 
genus Oryzomys, and, as might be expected from its structural characters, is aquatic in 
its habits, specially frequenting the dykes and dams of irrigated rice-fields, and swimming 
and diving with facility. For its addition to the Central-American fauna we are 
indebted to Dr. Coues, who observes that he cannot distinguish a Tehuantepec speci- 
men from the ordinary H. palustris of the United States. “In colour it is a little 
clearer than most Carolina skins, yet not of the paler yellowish-brown noticed in 
Kansas ones, but rather a brighter fulvous-brown; the underparts are unusually pure 
white”4. Two Mexican examples in the British Museum have rather more naked tails 
than United-States specimens ; but in other respects they do not show any approach to 
the next species. 
In the same monograph Dr. Coues doubtfully referred specimens of an Oryzomys 
from Jamaica to the present species. He has since informed me that it proves to be 
distinct ; but, as far as I am aware, he has not yet named or described it. 
10. Hesperomys couesi. (Tab. XV. fig. 1.) 
Hesperomys couesi, Alston, P. Z. 8. 1876, p. 756 (descr. orig.) *. 
Hab. Mexico (Geale; Verreaux, Mus. Brit.1); Guatemata, Coban, Choctum (Salvin 
& Godman, Mus. Brit.1; Mus. Berol.); Honpuras (Mus. Brit.). 
I have ventured to dedicate this handsome species to my friend Dr. Elliott Coues, 
whose recent labours have done so much to clear up the confusion into which the 
North-American Muride had fallen. 
Coues’s Rice-Mouse is certainly referable to the subgenus Oryzomys, being closely 
allied to the last species; it differs strikingly, however, in its long and almost entirely 
naked tail (the fine sparse hairs of which are hardly perceptible), its close, fine, and 
somewhat woolly fur, and its clear reddish-brown coloration, which varies in different 
specimens from dark red-brown to light rufous; it also appears to be a decidedly larger 
animal. From the character of the tail and fur it may be expected to prove less strictly 
aquatic in its habits than H. palustris. 
There are several specimens of Coues’s Rice-Mouse in the British and Berlin Museums, 
from Mexico, Guatemala, and Honduras; but I have not yet been able to trace its 
range beyond these States. 
The figure is taken from one of the typical Mexican specimens in the British Museum. 
11. Hesperomys nudicaudus. 
Hesperomys (Tylomys) nudicaudus, Peters, Monatsb. Ak. Berlin, 1866, p. 404, figs. 1-4, skull (deser. 
orig.) }. 
Hab. Guatemata (Mus. Basel.*). 
Professor Peters’s type is an adult female from Guatemala, which was submitted to 
