﻿360 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 102 



P^ven thougli these animals show no extenal eye, there is supposed to 

 be a minute, completely organized eye present under the skin. No 

 specimens have been examined. 



Family MURIDAE 



ARVICANTHIS NILOTICUS (Desmarest) 



Arvicola niloticus Desmarest, Mammalogie . . ., pt. 2, p. 281, 1822 (Egypt). 



Specimens examined. — Two. Beliera Province: Alexandria, 1 

 Fayum Province : Lake Fayum, 1. 



Description. — Dorsal hairs tipped with Ochraceous-Tawny, bases 

 and other hairs of the dorsum throughout their length, blackish; 

 strong admixture of blackish hairs on dorsum, becoming fewer on 

 sides and rump ; nose, ring around eyes and hairs of rump Buckthorn 

 Brown ; tail bicolored, blackish on dorsal surface, but sparsely haired ; 

 ears rather large, rounded and but finely covered with hair ; hairs of 

 belly, ventral surfaces of fore and hind legs white-tipped, these hairs 

 with blackish bases; immature pelage darker. Tail about equal to 

 head and body in length; hind feet rather long; thumb expressed as a 

 rudimentary claw only. 



Measurements. — One adult male from Lake Fayum, Fayum Prov- 

 ince, measured : Total length 321 ; length of tail 141 ; length of hind 

 foot 38 ; length of ear from notch 20 ; length of palate 16.9 ; length of 

 palatal foramina 8.5 ; crown length of upper molar series 6.5 ; length 

 of nasals 14.6 ; least interorbital width 5.4 ; weight 56.0. 



Remarks. — On superficial examination these animals are surpris- 

 ingly like the North American Cricetine genus Sigmodon., both ex- 

 ternally and cranially. From recorded habitat observations they 

 both occupy much the same ecological niche. 



RATTUS NORVEGICUS (Berkenhout) 



Mus norvegicus Berkenhout, Outlines of the natural history of Great Britain, 

 vol. 1, p. 5, 1769. 



^Specimens examined. — Twenty-eight. Behera Province: Alexan- 

 dria, 7. Suez Canal Zone : Port Said, 6 ; Ismaila, 8 ; Suez, 7. 



Description. — Upper parts near Verona Brown, no pure color, all 

 hairs on back black tipped and plumbeous based, with the intermediate 

 area of the above color ; sides, flanks and shoulders somewhat lighter 

 than dorsal color; throat, underside of forelimbs, entire belly and 

 dorsal surfaces of hands and feet, white; hairs of belly and throat, 

 plumbeous based ; tail blackish, but sparsely covered with short whitish 

 hairs, annulations distinct. Ears small; tail equal to or somewhat 

 less than head and body ; eyes small. Skull : Temporal ridges paral- 

 lel or nearly so posteriorly; anterior molar with small accessory cusp 

 on anterior edge. 



