200 U.S. NATIONAL MUSEUM BULLETIN 27 5 



According to Rode (1948), the Norway rat is abundant in all ports 

 of North Africa and occurs also in the large villages of the interior. 

 It is doubtful that they occur in the Saharan interior of Libya. These 

 rats are known to have a definite predilection for moist habitats and 

 frequently inhabit stream banks where they demonstrate marked 

 abilities for swimming and burrowing. Even in the tropics, they sur- 

 vive only where the habitat has been significantly altered by man. 

 Moist habitats in some of the larger oases of Cyrenaica and the 

 Fezzan may provide the ecological requirements of these rats, but 

 these areas are sporadic and localized. In addition, the barriers 

 imposed by vast areas of desolate sand and arid desert must be sur- 

 mounted before they could become established in these interior oases. 



In the present study, I collected extensively for several months in 

 the interior oases and made frequent inquiries regarding the local 

 rodent fauna. During this period I was unsuccessful in obtaining any 

 rats (R. rattus or R. norvegicus) and observed no indications of their 

 presence. 



Rattus rattus (Linnaeus) 

 Mus rattus Linnaeus, Syst. Nat., 10th ed., vol. 1, p. 61 (Sweden). 



General distribution of species. Nearly cosmopolitan owing to 

 its commensal relationship with man; it is said to occur in the wild 

 state in most of India, West Pakistan, Ceylon, foothills of the Hima- 

 layan Mountains, Southern China, Burma, Thailand, Laos, Viet Nam, 

 Malaya, and in the larger islands of the southwestern Pacific, including 

 the Philippine Islands. 



Distribution in Libya. Occurs commensally with man in the 

 larger coastal cities of Benghazi, Tripoli, and Derna and apparently 

 is present in the wild state in parts of coastal northern Cyrenaica. 



Specimens examined. Four, from Cyrenaica: 27 km E Apollonia, 

 3; 12 km NW Gubba, 1. 



Published records in Libya. Cyrenaica: Benghazi (Festa, 1925 

 [Epimys tectorum Savi]) ; Derna, Merg ( = Barce) (de Beaux, 1938 

 [Rattus rattus nericola Cabrera]); Tripolitania: Tripoli (Toschi, 1951 

 [Rattus rattus jrugivorus Rafinesque]) . 



Measurements. Measurements of an adult female, 325658, from 

 27 kilometers east of Apollonia, are: Total length 343; length of tail 

 192; length of hind foot 33; length of ear 24; greatest length of skull 

 39.7; condylobasal length of skull 38.2; alveolar length of upper mo- 

 lariform toothrow 6.9; greatest breadth across zygomatic arches 19; 

 least interorbital breadth 5.5; length of nasals 14.5; length of audital 

 portion of auditory bulla 7; palatal length 21.7; breadth of rostrum 

 at level of antorbital foramina 4 ; length of anterior palatine foramina 7. 



Diagnosis. Upperparts varying among shades of Prout's Brown, 

 Snuff Brown and Sepia; a large portion of the hairs of the shoulders, 



