238 U.S. NATIONAL MUSEUM BULLETIN 2 75 



Jaculus jaculus collinsi differs from the type and the type series of 

 J. j. whitchurchi in larger body size, longer tail, longer ears, more 

 variegated color of dorsum, paler flanks and lateral regions, smaller 

 lachrymals, wider rostrum, less vaulted braincase, heavier zygomata, 

 and generally larger cranial measurements. 



For comparison with Jaculus jaculus arenaceous, see account of 

 that subspecies. 



Animals from Gialo are noticeably paler and smaller in size than 

 those from the type locality which lies farther to the south, suggesting 

 intergradation with Jaculus jaculus whitchurchi, whose geographic 

 range is to the north. This similarity in color could best be inter- 

 preted as a response to the paler colored soils nearer the coast, inas- 

 much as extensive areas of sand and barren hamada occur between 

 Agedabia and Gialo. It is doubtful if genetic exchange is of common 

 occurrence across this barrier. 



Some of the type series were obtained from a large concentration 

 of sparsely vegetated dunes associated with date palms, and the re- 

 mainder were taken from among large clay hummocks at some distance 

 from the oasis proper. The latter area supported sparse growths of 

 Tamarix and Calligonum. 



The subspecific name collinsi is proposed in recognition of Alan 

 C. Collins, who made possible the trip to the Tibesti Mountains during 

 the early spring and summer of 1961. 



Jaculus jaculus cufrensis, new subspecies 



Holotype. Adult female, skin and skull, USNM 325785, from El 

 Giof, Cufra Oasis, Cyrenaica Province, Libya; obtained Apr. 2, 1962> 

 by G. L. Ranck, original no. 1898. 



Specimens examined. Seventeen, from Cyrenaica: El Giof, Cufra 

 Oasis, 15 (1 skull only); El Hauuari, Cufra Oasis, 2. 



Measurements. The averages and extremes of five males and 

 seven females from the type locality, with the measurements of the 

 type in brackets, are, respectively: Total length 279.8 (273-285), 

 282 (270-297), [290]; length of tail 172.8 (164-178), 174.9 (165-184), 

 [180]; length of hind foot 63.6 (61-65), 61.4 (60-64), [60]; length 

 of ear 21.2 (20-22), 21 (20-22), [20]; greatest length of skull 33.2 

 (33-33.6), 32.7 (32.2-33.5), [32.7]; condyloincisive length of skull 

 29.3 (28.8-29.8), 28.7 (27.8-29.7), [28.9]; crown length of upper molar- 

 iform toothrow 5.1 (4.8-5.4), 4.9 (4.7-5.1), [5.1]; greatest breadth 

 across zygomatic processes 21.8 (21.1-22.7), 21.8 (21-22.7), [22.7]; 

 least interorbital breadth 12.4 (12.1-12.9), 12.2 (12-12.5), [12.3]; 

 length of nasals 12.1 (11.8-12.5), 11.6 (11.2-11.9), [11.7]; breadth 

 of rostrum at level of antorbital foramina 4.8 (4.6-5), 4.8 (4.4-5.4), 

 [4.8]; greatest breadth of braincase 17.6 (17.2-18.1), 17.7 (17.4-18.2), 



