MAMMALS OF MINNESOTA. 207 



be closely 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, BAIRD. 



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 My odes (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 BD. 



Myodes ( Synaptomys) cooperi, BAIRD. Cat. in Mam. N. A., 1857. 

 Synaptomys cooperi, BAIRD. Mam. N. A., p. 558, 1857. 



COUES. Proc. Acad. Nat. Sci. Phil., 1874; Monogr. 

 Amer. Rodentia, 1877. 



QUICK 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 mammae (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 



