242 U.S. NATIONAL MUSEUM BULLETIN 2 75 



markedly smaller in size than either J. j. tripolitanicus or J. j. sefrius, 

 are interposed between their ranges. 



Remarks. Jaculus jaculus tripolitanicus is larger cranially and has 

 larger hind feet than any other subspecies of Jaculus jaculus in Libya. 



A single specimen from 40 kilometers east-northeast of Nalut, 

 Tripolitania, differs from the type series of J. j. tripolitanicus in 

 more uniform color of dorsum with more yellowish coat, less admix- 

 ture of dark-tipped hairs, and slightly larger hind feet. Cranially, 

 this specimen does not differ significantly from animals from Gharian 

 and is accordingly referred to J. j. tripolitanicus. 



This large subspecies is apparently confined to the more humid 

 environments of the Gefara Plain north of the Gebel Nefusa. 



Both the type series and the specimen from 40 kilometers east- 

 northeast of Nalut were taken from localized concentrations of 

 vegetated dunes near the escarpment of the coastal plain. Fresh 

 burrows were abundant in the sand throughout the traplines, sug- 

 gesting a high population density. Gerbillus aureus and Meriones 

 caudatus were also collected from this same habitat. 



The name tripolitanicus refers to the range ascribed to this sub- 

 species in northern Tripolitania Province. 



Jaculus jaculus whitchurchi, new subspecies 



Holotype. Adult male, skin and skull, USNM 325807, from 10 

 km S Agedabia, Cyrenaica Province, Libya; obtained June 18, 1962, 

 by G. L. Ranck, original no. 2362. 



Specimens examined. Thirty-one, from Tripolitania: 12 km W 

 Sirte, 3; 15 km WNW Marble Arch, 1; from Cyrenaica: 10 km 

 S Agedabia, 17; Giarabub, 8; 24 km SSE Giarabub, 1; Bahr el Tubat, 

 21 km ESE Giarabub, 1. 



Measurements. The averages and extremes of 12 males and 3 

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

 brackets, are, respectively: Total length 287.6 (280-296), 300.3 

 (294-305), [282]; length of tail 178.6 (174-182), 186.3 (184-190), 

 [177]; length of hind foot, 62.3 (59-64), 62.7 (60-65), [62]; length of 

 ear 21.4 (19-23), 21.7 (20-23), [21]; greatest length of skull 33.2 

 (31.8-34.5), 34.1 (33-34.8), [32.8]; condyloincisive length of skull 

 29.4 (28.5-30.4), 29.9 (29.3-31.1), [28.7]; crown length of upper 

 molariform toothrow 5.1 (4.7-5.4), 5.2 (5-5.4), [5]; greatest breadth 

 across zygomatic processes 21.7 (20-22.5), 23 (22.5-23.8), [21.9]; 

 least interorbital breadth 12.4 (11.8-13), 12.6 (12.4-13), [12.4]; length 

 of rostrum at level of antorbital foramina 4.8 (4.5-5.3), 4.8 (4.6-5), 

 [4.8]; greatest breadth of braincase 18 (17.1-18.9), 17.8 (17.5-18.2), 

 [17.1]; greatest breadth across antorbital processes 22.4 (21.3-23.8), 

 22.8 (22.6-23), [22.3]. 



