MAMMALIA. 
41 
clothed in the light-coloured fur which it had when inhabiting its desert- 
home. After three centuries more, having passed through about 900 gene- 
rations, we find evidence that it changed colour to black, probably under 
the influence of the diminished intensity of light and heat, hut without de- 
riving any perspicuous advantage from such a change. 
In an Appendix, the author adds notes on the external and 
internal characteristics of the different European species of Mus, 
and on the development and dentition of young Mus rattus. 
The Recorder trusts that this abstract will induce our readers 
to refer to the original of M. de Flsle^s paper, who deserves 
great credit, not for having abolished one of the infinite number 
of so-called species of Mus, but for having shown us, in a clear 
and convincing manner, the way to prove the identity or dis- 
tinctness of species. 
J/ws. Mr. Blyth has made short remarks on numerous Indian species of 
tliis genus ; however, little or no progress can be made in their investiga- 
tion until much better specimens are available for examination, Journ. As. 
Soc. Beng. 1865, pp. 192-194. 
Mus decumanus. A specimen suffering from hypertrophy of the skin has 
been observed by Mr. T. E. Gunn t Zoologist, 1865, p. 9645. See also a note 
on the same subject by Mr. E. R. Alston, ibid. p. 9708. This disease does 
not appear very uncommon among mice and rats, and there are notes on, 
and figures of, such individuals in Proc. Zool. Soc. 
Mus. Prof, de Eilippi found one species only of this genus (AT. silvaticus) 
in Western Persia, M. musculus and M. decumamis being absent. Viaggio 
in Persia, p. 344, 
\piatacanthomys (Blyth). Prof. Peters has removed this genus from the 
Myoxina to the Murina, and characterizes it thus: — Habitus myoxinus. 
nostrum acutum, rhinario nudo, labro fisso ; oculi mediocres ; auriculaB me- 
diocres, nudae ; vellus molle, setis dorsalibus latis, sulcatis ; artus mediocres ; 
palmaB plantreque pentadactylae, digito primo abbreviate, falculis modicis 
curvatis, acutis ,• cauda villosa, versus apicem fere disticha. Dentes priinorrs 
laeves, compressi, acuti ; molares utrinque 3 , complicati. Cranium miirinum, 
sed foraminibus incisivis parvis, coarctatis ; ossibus intermaxillaribus inclusis, 
palato perforate et processu coronoideo brevissimo. Ossa antibrachii se- 
juncta, cruris connata. — The species, P. lasiurus (Blyth), is described and 
figured (with the skull). Proc. Zool. Soc. 1865, p. 397, pi. 20. 
'ACricetomys gamhiamis. Prof. Giebel has described external and osteological 
characters of this Rodent. Zeitschr. gesammt. Ntrwiss. xxvi. 1865, pp. ISG- 
139. 
ACricetus isahellinus, sp. n., De Eilippi, Viaggio in Persia, p. 344, from 
Teheran. 
Arvicola. Prof, du Bocage, in the memoir mentioned above (p. 5), dis- 
tinguishes and describes three species occurring in Portiigal-T— -4. musignani 
(Selys), A. inccHus (Selys), and A. roziamis, sp. n. j the zoological and ana- 
tomical distinctive characters are pointed out, and the new species, its skull 
and dentition are figured. 
