MYOPUS 183 



Ground-colour of the rest of the body dark grey or slate, lightened 

 by silver hairs, which are abundant everywhere, and particularly 

 so on the ventral surface ; a few silver hairs also ajjpear through 

 the rusty mantle in the jieighbourhood of the rumj). Hands 

 concolorous with sides. Feet dark brown (near " sepia '") above, 

 bufiy brown below. Tail black above, bufEy brown below. 



Skull, compared with that of M. schisticolor, with the rostrum 

 shallower and longer, the diastema a little longer, and the nasals 

 less steeply inclined. Squamosals more closely approximated 

 anteriorly, indicating an increased develojiment of the anterior 

 portions of the temporal muscles apparently in correlation with 

 larger molars ; the distance between the squamosals in front 

 1-1 mm. instead of 2-3 as in an equal-aged skull of M. schisticolor ; 

 the bistejihanic width 3-9 instead of 4-7. Posterior edge of 

 palate gently convex centrally, instead of being furnished with 

 a small median spinous process. Pterygoid fossae shorter. 

 Auditory bullae greatly enlarged and globosely inflated. 



Upper incisors slightly stronger and a little more recurved 

 than in M. schisticolor, in section more closely resembling those of 

 Leiiunus. Cheek-teeth noticeably larger and broader but exactly 

 like those of M. schisticolor in form. 



For cra)iial and external diinomons, see tables at end of 

 volume. 



Remarks. — The type is the only specimen known to me, but 

 G. M. Allen has lately referred to this species a fine series of 

 fourteen from the neighbourhood of Urga and four from Sain 

 Noin Khan, Northern Mongolia, obtained by the Second and 

 Third Asiatic Expeditions of the American Museum. 



4. Myopus middendorfli Vinogradov. 



1853. Ml/odes schisticolor Middendorff, Sibirische Reise, 2, Th. 2, 



p. 108. 

 1922. Myopus middendorfji Vinogradov, Ann. Mus. Zool. Acad. Sc. 



Russ., 23, pp. 374 (name only), 512. 



Type. — -Zool. Mus. Acad. Sc. Russia (Leningrad), No. 72; 

 collected August 19, 1845, by Wosnessenskv. (Skin and imperfect 

 skull.) .VI 



Type locality. — Aldoma River, near Avan, west coast of the 

 Sea of Okhotsk. 



Range. — From the Okhotsk coast and northern Amur Land 

 westwards to the eastern shore of Lake Baikal. Vinogradov 

 records the " type locality " as " upper course of the river Maly 

 (Small) Okonon, Yablanovy Ranges, Northern part of Amour- 

 Land, "" but gives the locality of the type specimen as " Aldoma 

 River, etc.,"' as quoted above. He states also that the species 

 occurs on the Bargusinsky Range, east coast of Lake Baikal. 

 I Characters. — Hind-foot 15-16-3 mm. ; condylo-basal length 25- 

 |26*2 mm. Like M. thaycri, but with the rufous mantle more 



