MURIDH—ARVICOLINM—ARCTIC ARVICOLA. 191 
(“tinged with red”—A. & B.): “a slightly hairy scaly tail more than half the 
length of the head . . . 14%” (according to A. & B. only 1.00); “above dark 
brown”; “head and body 412”, &c. Audubon's figure shows a bricky-red 
animal all over, with an extraordinarily short tail. But the tints of his plates 
are thoroughly unreliable, and measurements of the type sent us by Dr. 
Sclater are,—head and body 5.50, tail 1.50; while the same gentleman speaks 
of the color as ‘above, rather dark mouse-brown; beneath, much paler, 
grayish”. Some of Richardson’s expressions point to Evotomys rutilus, and, 
indeed, it seems almost impossible that he should not have included this 
abundant animal in checking off his five common species; but other charac- 
ters assigned are totally incompatible. We should further remark that the 
ascribed length of the hind foot, 0.55, is less than we ever found for any 
species excepting the diminutive A. oregonus. We find it impossible to iden- 
tify Richardson’s “noveboracensis? Raf.” 
A. ‘‘pennsylvanicus Ord” is another of Richardson’s species; it has 
usually been assigned to the ordinary pennsylvanicus of the United States 
(=riparius), and in all probability belongs there. He says it is “ very 
abundant from Canada to Great Bear Lake”, in which region we are pre- 
pared to show that the true siparius occurs; most of the puzzling specimens we 
shal] presently treat of coming from extreme Arctic and Northwestern areas. 
It is true that Richardson puts the total length (‘345 inches”) under average 
riparius; but this seems to be an error, for Dr. Sclater’s recent measurement 
of them shows 4.70, while there is certainly an error (probably typograph- 
ical) in the ascribed length of head (“27%”', for not even the biggest 
xanthognathus, 7 inches long, has such a head as this implies. On the whole, 
there is little risk of error in assigning Richardson’s ‘ pennsylvanicus Ord” 
as a complete synonym of true riparius. We will also bear in mind that 
Richardson states positively it is what Sabine described in Franklin’s Jour- 
ney under the (erroneous) name of xanthognathus. 
Of a sixth species, less fully noticed by Richardson, from Bering’s 
Straits, under name of Arvicola rubricatus, we know nothing. But we do 
not believe that this (or any other Avvicola) ever had the sides (or any other 
part of the body) “scarlet”, as alleged, or even “nearly scarlet”, as said by 
Audubon and Bachman. We believe, however, that this animal will prove 
to be an Evotomys, very vear if not the same as Mus ruti/us Pallas, with which 
Richardson has uot shown himself acquainted, though we cannot imagine 
how he overlooked it, as it appears he did. 
