MAMMALIA RODENTIA. 43 



flavcsceus, supra apiccm elongato-nigropilosa." Body 4", tail without hair 

 4" ] ". From Bahr el Abiad. Suudevall finds it very like M. pygargus, 

 with which I consider it to be identical, and am also fully of opinion, that it 

 may be the full grown condition of the former. (3) M. murinus, u. sp. 

 " Supra fulvesceus, fusco-mixtus," naso cristato productissimo ! auriculis 

 rotundato-oblongis ; cauda corpore lougiore, postice uudique nigricaute 

 pilosa." Body 5|", tail with hair almost 6". Prom Bahr el Abiad. As 

 Suudevall himself says, this species very much resembles Gerbillus pyra- 

 i.iii/i't/i, although F. Cuvier's figure of the cranium differs from it, on which 

 however I place no importance, as those drawings are not very exact. 

 (4) M. crassus, u. sp. " Pallide fulvesceus, vellere quoque laterum basi 

 cincreo; cauda breviore, plauta brevi." Body above 5", tail without hair 

 3" 3'". From the Desert of Sinai. The latter species, which clearly 

 belongs to Rhomboiiiys, is very similar to rny Rhombomys pallidus, but differs 

 from it apparently in the remarkable shortness of the tail. 



A third species of Oxymycterus has been characterized by 

 Pictet in the Mem. de Geneve, x, I. (1843) p. 211, tab. 

 iv and v, figs. 9-14. 



He calls it 0. Mspidus ; lively red above, sprinkled with black ; beneath 

 grayish brown, with a yellow tinge ; tail much longer than half of the body. 

 Body 6", tail 4" 2'". Upon comparing it with 0. rostellatus and nasatm, 

 1 find it differs specifically from both of them. 



Quatrefages has prepared the article " Campagnol" (Arvicohi) for the 

 'Diction. Univers. d'Hist. Nat.' iii, p. 95, but certainly not in the way 

 demanded by the present condition of therology. 



Of his Arvicola incertus, Selys says (Rev. Zool. 1843) that he had obtained 

 it from the Department of the Var and from Montpellier. Althougli he 

 thinks that it differs from A. Xacii only in the circumstance that in A. 

 incertus the fur is lighter than in that species, and in its yellow tinge on the 

 sides approaches more nearly to that of A. arvalis and socialis, this differ- 

 ence is of very slight importance, for Pecchioli states, that not only in 

 A. Sacii do the sides generally pass into a yellowish hue, but the young 

 have a yellow fur, which only gradually passes into an ash gray. A very 

 copious description, particularly of the habits of this A. Savil, has been 

 given by Pecchioli. (Isis, 1843, p. 688). 



In the ' Ann. des Sc. Nat.' Martius has now described in detail his 

 Arvicola nioalis, from which its identity with my Hypudccus alpi/ius is 

 evident. 



De Kay (Nat. Hist, of New York, i) has distinguished two new North 

 American species of Arvicola : (1) A. rufesceitx, " above clear reddish brown, 

 beneath slaty ; tail longer than the head." Body 3", tail 2" (2) A. onc'ulu, 



