14 r,'i-lih New Lemming 



117///r 



General r/mn/r/o 1 *.-^ Larger than S. imitii/tix, with larger skull and longer 

 hind foot and tail. 



Color of type. Upper parts sepia brown, quite thickly interspersed with 

 black-tipped hairs, the fur basally blackish slate; each side gland 

 marked with white ; under parts grayish white ; inside of ears slightly 

 darker than general color of upper parts ; a few hairs at base of ears and 

 on sides of cheeks, light chestnut ; tail quite sharply bicolored, the upper 

 and lower sides concolor with body. 



Cranial characters. Compared with the type of Synaptomys innuitux, 

 which is approximately of the same age, the skull of .S 1 . sphagnicola is 

 much larger and longer ; interorbital constriction considerably longer and 

 narrower; rostrum longer and stouter; braincase more lengthened pos 

 teriorly ; posterior production of zygomata straighter ; incisive foramina 



much larger and slightly longer 

 proportionally ; post - palatal 

 pits deeper and median ridge 

 correspondingly conspicuous ; 

 audital bulhe longer and more 

 rounded ; pterygoids more di 

 verging ; mandible larger and 

 stouter, with condylar pro 

 cesses broader proportionally. 

 Dental characters. Com pared 

 with S. innuitus, the molars are 

 heavier and molar series consid 

 erably longer ; enamel pattern 

 of molars not essentially differ 

 ent, though the posterior prism 



FIG. 3. a, Type skull of Synaptomys (Mictomys) o f the last Upper molar is more 



Inner faces of the 

 upper ncsors much exca 

 vated medially, with the edges 



exterior to the sulci about one millimeter longer than remaining portion 

 of the teeth, and ending in sharp points. Enamel faces of incisors paler 

 orange than in the type 'of S. innuitus. 



Measurements. Type of S. sphagnicola (in flesh): total length 132; tail 

 vertebrae 24; hind foot 20. Type of S. innuitus (in alcohol) : total length 

 115; tail vertebrae 17; hind foot 17.5. 



Cranial measurements of type. Occipito-nasal length 27.5; basilar length 

 26; zygomatic breadth 16; mastoid breadth 12; interorbital constric 

 tion 28 ; length of nasals 8 ; length of incisive foramina 5.5 ; upper molar 

 series, 7. Type skull of S. innuitus ( No. 24729, U. S. Nat. Mus.) : occipito- 

 nasal length 19.6; basilar length 18.3; zygomatic breadth 15; mastoid 

 breadth 11.5; interorbital constriction 3.1; length of nasals 6. 3; length 

 of incisive foramina 4.8 ; upper molar series 6.5. 



General remarks. The discovery of a species of Mictomys in the White 

 Mountains, within the limits of the Canadian Zone, and at a compara 

 tively low altitude (about 1 ,600 feet) is one of the many surprises that mod- 



b, type skull of Synaptomys (Micto- triangular. 



