1922] Allen, Congo Sciuridse, Anomaluridse , Idiuridse 69 



taken March 16 with the eight taken January 25, shows that the latter 

 average darker in general effect and the hair-tips paler, yet certain speci- 

 mens of the January series can be matched exactly by the paler speci- 

 mens of the March series. The hair-tips on the back of the brighter 

 colored examples of the March series are near snuff-brown, varying in 

 intensity in different individuals, and about cinnamon-buff on the ventral 

 surface, but often nearly wanting through wear, as in the single Avakubi 

 specimen taken January 22, the most worn of any of the entire series of 

 twenty skins. 



A single skin and skull 1 of I. zenkeri, from the southern Cameroon, 

 and thus practically a topotype, is rather darker than the average of the 

 Medje series, but differs so little from some of them that they are provi- 

 sionally referred to this species. Their relationship to /. zenkeri kivuensis, 

 recently described by Lonnberg, 2 is not at present determinable. It 

 appears to be a much darker form than typical zenkeri. 



Idiurus langi, new species . 

 Plate V 



Type, No. 50542, <? adult, Medje, Belgian Congo, March 16, 1910; Herbert 

 Lang and James P. Chapin, American Museum Congo Expedition. Orig. No. 737. 

 Named for Herbert Lang, leader of the American Museum Congo Expedition. 



Size of and proportions nearly as in Idiurus macrotis Miller, but very different in 

 coloration. 



Upperparts (type, in fresh, unworn pelage) washed with clay-color (Ridgway, 

 1912), strongest on middle of back, less heavily on lower back and sides; in worn 

 pelage much paler (about cinnamon-buff), the light hair-tips partly worn off (almost 

 wholly on lower back and sides) ; pelage of middle of back (in fresh coat), 11.5 mm. 

 in length, the buffy tips about 2 mm. long, followed by a dark zone of about equal 

 width, the basal two-thirds "mouse-gray." Underparts heavily washed with warm buff, 

 almost wholly concealing the light neutral gray of the basal fur (varying in different 

 specimens, especially when worn) to a faint wash of lighter tone) ; a conspicuous pale 

 yellowish white patch on sides of nose extending from base of rictal bristles to the 

 naked nose pad, about 4X6 mm. in extent; chin and interramal region white or 

 pale yellowish white ; upper surface of membranes thinly clothed with brownish black 

 hairs, under side nearly naked; membranes and ears pale brownish (ears in some 

 specimens slightly darker brown) ; feet and greater part of tail yellowish brown, the 

 long tail hairs dark brown with a faint tone of chestnut, much less dark than in /. 

 macrotis. The scale pad on the ventral base of the tail is much longer than in macrotis 

 (given as 17 mm.), varying from 20 to 25 mm. in length, and the scales are larger and 

 tend to form regular rows, and beyond what may be considered as the "scale pad" 

 proper, the annulations on the lower surface of the tail are conspicuous and roughened, 

 so that in some specimens it is difficult to determine what should be regarded as the 



iNo. 125438, U. S. Nat. Mus., 9 , Efulen, Bulu Country, Cameroon, July 21, 1903, coll. G. L. Bates. 

 2 1917, Kungl. Svens. ventensk. Akad. Handl., LVIII, No. 2, September, p. 67. Masisi, Belgian 

 Congo, about forty miles northwest of Lake Kivu. Two specimens, adult and young. 



