70 Bulletin American Museum of Natural History [Vol. XL VII 



apical end of the pad, as distinguished from the annulations. The fringes on outer 

 edge of both fore and hind feet, the small tufts of whitish bristly hairs at tarsal and 

 metatarsal joints, the tail fringes, and the scattered long hairs in the dorsal pelage, 

 are evidently generic characters, being common to the three forms of Idiurus here 

 under consideration. 



Collectors' measurements of the type 1 : Total length, 224 mm.; head and body, 

 94; tail vertebrae, 130; hind foot, 20; ear, 18. 



Collectors' measurements of type and 4 topotypes (all adult males): Total 

 length, 218 (207-224); head and body, 91 (86-94); tail vertebrae, 129 (124-133); 

 hind foot, 21 (20-22); ear, 15.7 (14-18). 



. Skull (measurements of type 1 ): Greatest length, 26; zygomatic breadth, 16; 

 least breadth of frontals, 2 6.6; greatest breadth of nasals, 2 3.2; upper toothrow, 3.5; 

 distance between inner bases of m 3 , 1.4; do. m 1 , 1.1; greatest length of mandible, 

 16.4; greatest depth (at coronoid), 10.2; lower toothrow, 4. 



Skull (type and same 4 topotypes) : Greatest length, 25.8 (25.1-26.2) ; zygomatic 

 breadth, 15.5 (15.0-16.0). 



Represented by 6 adult males, all of which are skins with skulls, and 1 adult female 

 in alcohol, all taken at Medje, January 25 (5 specimens) and March 16 (2 specimens), 

 1910. 



The type is the only specimen in fresh, wholly unworn pelage. All the others 

 show more or less wear, especially on the lower back and sides, and they vary much 

 in the amount of buffy wash, both above and below, and form a graduated series from 

 clay-color to a pale tone of buff on the upperparts, and on the lower parts from a 

 strong yellowish wash to only a faint pale tone where the hair-tips are least worn. 

 The two March 16 specimens differ greatly from each other in coloration and amount 

 of wear; the January series of skins (all taken January 25) differs similarly in respect 

 to amount of wear and consequent tones of color on both upper and lower surfaces. 



Idiurus langi is smaller than I. macrotis in external measurements, 

 but the cranial measurements are practically the same. It differs, how- 

 ever, strikingly in coloration, both above and below, the general color 

 being much lighter, especially in respect to the basal fur, ears, and mem- 

 branes. I. langi differs from I. panga in much larger size and in colora- 

 tion, especially of the ventral surface, which has a pinkish tone in panga 

 instead of yellowish, and the upper surface is much more heavily washed 

 with buff. The yellowish white, sharply defined nose spot of langi will 

 alone readily distinguish it at a glance from either macrotis or panga. 



Idiurus panga, new species 



Type, No. 50605, 9 adult, Panga, Belgian Congo, September 18, 1914; Herbert 

 Lang and James P. Chapin. American Museum Congo Expedition. Orig. No. 2552. 



Similar to Idiurus macrotis Miller 3 , but much smaller and considerably paler 

 throughout, including the basal fur. 



*For measurements of i". macrotis see p. 71, where they are given in comparison with I. panga. 



2 Fronto-nasal sutures solidly ankylosed and indistinguishable, so that length of frontals and nasals 

 cannot be given. 



3 Idiurus microtis Miller, 1898, Proc. Biol. Soc. Washington, XII, pp. 73-76, figs. 15-19 (skull, 

 ear, foot, and tail). Efulen, Cameroon District, West Africa. 



