222 Merriam — Descriptions of Five New Rodents. 



Microtus kadiacensis sp. nov. 



Tijpc fniin Kadiak Lslaiid, Alaska. No. 65827, 9 ad. U. S. Nat. Mus., 

 Biological Survey Coll. Collected Sept. 12, 1.S93, l)y B. J. Bretherton. 

 Original No. 213. 



General characters. — Similai' to M. silkenxift in color and general appear- 

 ance, but much smaller, somewhat paler, and under parts white instead 

 of ochraceous bufl"; tail and ears rather short. 



Color. — Upper jjarts uniform grizzled pale brownish with pale dull ful- 

 vous suffusion, not conspicuously lined with black hairs; under parts 

 l^lumbeous, stnjngly washed with pure white ; tail sharply bicolor, dusky 

 above, white beneath; fore and hind feet grayish brown. 



Cranial and dental characters. — Skull similar to that of M. sltkensls, but 

 very much smaller ; interparietal much more elongated transversely and 

 nan-ower ; audital bulUe very much smaller and narrower ; postpalatal 

 pits deeper; teeth essentially as in sitkcnsis, hut first lower molar with 

 only 2 completely closed loo])S on each side. 



Measurements.— Type specimen, measured in flesh by collector: total 

 length, 141; tail vertebrte, 23 [probably 33] ; hind foot, 18 [probably li) 

 or 20]. Cranial ineasurevieiits : basal length, 23.5 ; zygomatic breadth, 13.5 ; 

 l)alatal length, 12.8; interorbital constriction, 3.8. 



Microtus unalascensis sp. nov. 



Type from Unalaska, Alaska. No. lU^h ? ""■ U. S. Nat. Mus., Bio- 

 logical Survey Coll. Collected Aug. 13, 1891, by C. Hart Merriam. Orig- 

 inal No. z. 



General characters. — Similar to M. kadiacensis, bnt apparently somewhat 

 darker; audital bullae much shorter and more globular; front lower 

 molar witli two closed and two open loojis on inner side, and two closed 

 and no open loops on outer side. 



Color. — (Specimen immature): Upper parts yellowish brown, darkest 

 on head ; under j)arts plumbeous "washed with whitish ; tail sharply bi- 

 color, narrowly 1>Iack above, broadly white below; fore and hind feet 

 grayish. 



Measureiiniits. — Type specimen (not full grown) : total length, 122; tail 

 vertebrfe, 28; hind foot, 19. 



liemorks. — This species, which resembles M. rutdceps of Europe in the 

 enamel pattern of the first lower molar, is closely related to 3f. kadiacen- 

 .S-/.S, from which it may be distinguished at a glance'by the much shorter 

 and more globular audital bulUe and the pattern of m i. 



During the single night spent at Unalaska on my return from the Seal 

 Islands, I caught several of these Voles along the edges of a small pond 

 on the outskirts of the Aleutian village of Iluliuk. Unfortunately, all 

 but one were eaten by Ravens shortly after daylight. The one secured 

 had dragged the trap into the water and drowned out of reach of the 

 Ravens. 



