MAMMALS OF MINNESOTA. 207 
. beclosely lined with silvery. The fur of the belly is plumbeous 
basally and nearly white apically. There is no sharp line of 
demarkation between the color of the sides and that of the 
belly. ‘Tail bicolor, the light color of the under surface reach- 
ing well up on the sides.” 
‘Other specimens from Elk River have the upper parts 
strongly suffused with brown, and the belly strongly washed 
with cinnamon, while in others the under parts are of the 
‘muddy rust color’ so often seen in true austerus.” 
GENUS SYNAPTOMYS, BaIrp. 
This-genus, charcterized by Coues as ‘‘the most remarkable 
genus of the family,” is very capricious in its distribution and 
thus is considered very rare. 
‘‘Root of inferior incisor ending abruptly opposite the last 
lower molar. Faces of superior incisors longitudinally grooved 
near the outer edges. Construction of molars and general 
cranial characters as in Myodes (Lemmings); palate ending’ as 
in typical Arvicola; external characters as in Arvicola; ears 
equaling or overtopping the fur; tail equal to or longer than’ 
the hind foot; pelage very soft and full.” 
Synaptomys cooperi Bop. 
Myodes ( Synaptomys) coopert, BAIRD. Cat. in Mam. N. A., 1857. 
Synaptomys cooperi, BAIRD. Mam. N. A., p. 558, 1857. 
Cougs. Proc. Acad. Nat. Sci. Phil., 1874; Monogr. 
Amer. Rodentia, 1877. 
QvUICK and BUTLER. Am. Nat., Feb., 1885. 
The only specimen of the single species of Synaptomys as 
yet found in Minnesota was collected by O. E. Garrison in 
Benton county and is at present in the National Museum 
(No. 10575). The pelage is described as very soft and full, 
and the color as much resembling A. riparius. Messrs. Quick 
and Butler have given the following information regarding the 
habits of this interesting species: It breeds from February to 
December, and was never known to bring forth more than four 
young at one time. There is one pair of pectoral and one pair 
of inguinal mamme (Coues says two pairs of pectoral and one 
pair of inguinal). In color, specimens are, as a rule, darkest 
when just reaching maturity. The nest of this species is always 
under cover, generally in a hollow stump or log, and is composed 
