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



Collectors' measurements of the Niangara series (6 males, 4 females) : 

 Total Length Head and Body Tail Vertebrae Hind Foot Ear 



c? 478 (470-488) 223 (216-235) 250 (245-260) 57.3 (54-59) 18.7 (17-19) 

 9 467 (455-479) 217 (215-227) 250 (242-257) 55.0 (53-56) 18.5 (17-20) 



Skulls, same specimens: 



Greatest Length Zygomatic Breadth 



( = occipito-nasal length) ( = greatest breadth) 

 c? 52.4 (51.0-54.0) 30.3 (29.1-31.3) 



9 51.7 (49.2-55.7) 30.8 (28.8-32.0) 



This form is readily distinguishable from those recorded below from 

 localities more to the southward, including Medje, Niapu, and Avakubi, 

 by its much paler general coloration and very much lighter under parts. 



Heliosciurus rufobrachium medjianus, new subspecies 



Heliosciurus rufobrachiatus pasha Thomas, 1915, Ann. Mag. Nat. Hist., (8) 

 XVI, December, p. 473, (part). The Medje and "Poko" specimens. "Poko" = 

 south of Poko, in forest probably nearer Niapu than Poko. 



Type, No. 50761, 9 adult, Medje, Belgian Congo, January 17, 1910; Herbert 

 Lang and James P. Chapin. Orig. No. 487. 



Larger and darker than H. r. pasha, the underparts very much darker, the white 

 tips of tail hairs much shorter, inside of limbs with much more rufous. Differs from 

 H. r. rubricatus in lacking the strong rufous suffusion of the underparts and the intense 

 rufous of inside of limbs, throat and anal region. 



Collectors' measurements of type: Total length, 502 mm.; head and body, 224; 

 tail vertebrae, 278; hind foot, 59; ear, 20. 



Skull (type): Greatest length (= occipito-nasal length), 53.6; condyloincisive 

 length, 49.3; least interorbital breadth, 15.8; tip to tip of post orbital processes, 23.7 

 postorbital breadth, 16.1; breadth of braincase, 22.2; zygomatic breadth, 30.7 

 length of nasals, 16.1; breadth of nasals anteriorly, 8.4, do. at posterior border, 5 

 length of maxillary toothrow, 10. 



Represented by 36 specimens (of which 23 are topotypes), taken as follows: 



Avakubi, north side of Ituri River toward Bosobangi, 1 ( cf adult), April 11, 1914. 



Bosobangi, 1 ( 9 adult), December 24, 1909. 



Gamangui, 1 (d 71 adult), February 7, 1910. 



Medje, 23 (13 adult, 10 immature) : 9 (6 c?, 3 $ , all adult), January 15-20, 1910; 

 10 (5 c?, 5 9, all immature, ranging in age from nurslings to half-grown), April 10, 

 August 3-September 14, 1910; 4 (2d", 2 9 , adults — 1 c? complete skeleton), March 

 22, 1910; February 28, April 2, 6, 1914. 



Niapu, 9 (7c?, 2 9, of which 6 are adult and 3 immature), November 14- 

 December 8, 1913. 



Akenge, 1 ( 9 adult), October 16, 1913. 



Collectors' measurements of 13 adults (8 cf, 5 9 ) from Medje: 

 Total Length Head and Body Tail Vertebras Hind Foot Ear 



cf 497 (441-534) 241 (225-254) 256 (211-292) 58.4 (55-62) 18.5 (17-20) 

 9 495 (475-502) 231 (224-238) 264 (246-278) 57.5 (56-59) 18.2 (17-20) 



