970 MR. OLDFIELD THOMAS ON [DeC. 15, 



this intermediate form, and 11 of tlie desert ordincdis, I have 

 felt justified in indicating their respective degrees of differences 

 by subspecific names. All are of coui-se members of the widely 

 spread species E. asiailcus, with the eastern uthensis type of 

 which the Imperial Tombs specimens mentioned in a previous 

 paper tend to connect the true senescens. 



The country in which this Chipmunk is found is mountainous 

 and broken, while E. a. ordinalis inhabits the flat region 

 bordering the sandy Ordos. 



12. ClTELLUS MONGOLICUS M.-Edw. 



J. 1731. Ching-pien, KW. Shen-si. 5100'. 



^. 1738. $. 1734, 1746. Ordos Desert, N.W. of Ching- 

 pien. 4900'. 



S. 1747, 1851, 1863, 1864, 1868. ?. 1748, 1858, 1865. 

 Yu-Iin-fu, Shen-si. 4000'. 



These specimens agree closely in their general sandy coloration 

 with Milne-Edwards's figure of mongolicits, and with the example 

 obtained by Swinhoe near Suen-hwa-fu in 1863,* which may be 

 accepted as a topotype, for David collected a number of his 

 " Mongolian " specimens at this latter place, which is below, not 

 on, the true Mongolian plateau. 



On the other hand, our Mongolian plateau sjoecimens, both 

 those collected by Mr. C. W. Campbell at Hara Ussu in 1898, and 

 by Mr. Anderson at Taboul in 1907 f, are so markedly darker in 

 colour that they might be recognized as a special plateau sub- 

 :Sj)ecies as follows : — 



CiTELLUS MONGOLICUS UMBRATUS. 



Thos. Abstr. P. Z.¥. 1908, p. 44 (Dec. 15). 



Size and proportions as in true mongolicus. Colour much 

 darker and greyer, speckled with blackish and buflfy, so as to 

 result in a tone rather darker than Eidgway's " Isabella.'"' Crown 

 near broccoli-brown, mai-kedly darker and less fawn than in 

 mongolicus. Under surface broadly washed with buffy, lips and 

 chin white. Sides of neck, front of forearms, and back of lower 

 legs more sti-ongly sufiused with tawny or tawny ochraceous than 

 in mongoUcifs, in which the colour is sandy or bufty. Tail-hairs 

 much shorter than in 'niongolicus, though this is probably a 

 ■seasonal character, cream-buft" at their bases and tips, their 

 middles black, none of the strong ochreous-bufi" colour showing on 

 the upper side ; below the middle line is ochraceous bufi^", but far 

 narrower and less conspicuous than in mongolicus. 



Dimensions of the type, measured in flesh : — 



Head and body 197 mm. ; tail 62 ; hind foot 37. 



Skull — greatest length 46-3 mm. ; basilar length 37 ; zygo- 

 imatic breadth 28 ; length of upper tooth-series 10. 



* See P. Z. S. 1870, p. 445. 

 ■f See P. Z. S. 1908, p. 105. 



