58 Merrimn — The Lonmiugs of the Genus Synaptomys. 



Sub<,renuH SYNAPTOMYS Baird. 

 Synaptomys cooperi Baird. 



Siinaptomyi^ cooperi Baird, ]\Iammal.s N. Am., pp. 550-558, 1857. 



Cones, Proc. Acad. Nat. Sci., Pliila., p. 194, 1874; INIonog. N. Am. 

 Kudcntia, pp. 235-23(), 1877. 



Quirk and Butler, Am. Naturalist, XIX, 11.3-115, Feb., 1885. 



Merriam, Proc. Biol. Soe. AVasli., A' II, 175-177, Dec, 1892. 



Bangs, Proe. Biol. Soc. Wash., IX, 99-104, April, 1894. 

 Synaptomys stonei Ehoads, Am. Naturalist, XXVII, pp. 53-54, Jan. 11, 1893. 



lype locality unknown ; probably northern New Jersey or southern New 

 York. 



Geograplilc distiibution. — Boreal and parts of Transition zones from INIin- 

 nesota eastward to eastern Massachusetts and south to Iowa, Indiana, 

 and Maryland, and in the mountains to North Carolina and Teniiessee. 

 South of the Boreal zone it appears to be confined to cold sphagnum 

 swamps, which give it a boreal atmosphere. 



General characters. — Similar in size and general appearance to Microtus 

 pennsylvavic'us, but tail very much shorter. Contrasted with Synaptomys 

 helaletes the feet are smaller and the rostrum, mandible, and upper incisors 

 are much narrower and less massive. 



Color. — Uj^per parts grizzled gray and yellowish brown abundantly 

 mixed with l)lack-tipped hairs ; under parts soiled whitish, the plumbeous 

 under fur showing through ; tail bicolor ; brownish above, whitish below. 

 In the adult the color of the back varies from pale yellowish lu'own to 

 almost rusty, always ' grizzled ' by a bountiful admixture of lilack-tipped 

 hairs. In the young the color is at first very dark, almost blackish slate ; 

 it then becomes grayish brown and approaches sepia before taking on the 

 yellowish brown of the adult. 



Cranial and dental characters. — Contrasted with 

 »S'. helaletes from Dismal Swamp, the skull and 

 teeth of S. cooperi are smaller and weaker, the 

 zA'gomata more bowed outward, the rostrum and 

 mandible very much narrower, the nasals nar- 

 rower posteriorly, and the brain case sliorter. 

 Fig. 2.- Enamel pattern of Measurements. — Average of 4 specimens from 

 upper and lower molars ^^u Arbor, Michigan: total length, 118; tail 

 in smafiio.o's cooperi. ^^^^^y^^^^ 17.5 . hind foot, 18. Average of 2 

 from Roan Alountain, North Carolina: Total length, 121 ; tail vertebne, 

 20; hind foot, 19.5. 



Synaptomys fatuus Bangs. 



Synaptomys fdtuiix Bangs, Proc. Biol. Soc. Wash., X, 47-48, March 7, 1896. 



Type locality. — Lake Edward, (Quebec. 



Geographic distrilnition. — Hudsonian zone from T^ake Edward, Quebec 

 (and probably much farther west), to Victoria county, New Brunswick, 

 and Godbout, Quebec. Limits of range unknown. 



General characters. — Similar to S. cooperi, but slightly smaller; skull de. 

 cidedly smaller, with much narrower ui)j)er incisors. 



