﻿MAMMALS FROM THE NILE DELTA REGION, EGYPT SETZER 357 



such time as a concerted effoi-t is made to obtain specimens and to 

 study this genus throughout its range, all of the animals cited above 

 are here referred to GerhiHus fyramiduni pyramidum. 



PACHYUROMYS DUPRASI NATRONENSIS De Winton 



Facliyurotnys dupresi (sic) natronensis De Winton, Nov. Zool., vol. 10, p. 285, 

 August 25, 1903 (Ulr Victoria, on the way to Wadi Natron from the Nile 

 Valley, Egypt). 



Specimens examined. — Two. Giza Province: West of Abu Rau- 

 wash, Cairo area, 1 (MVZ). Egj^pt: Presumably near Cairo, 1. 



Description. — Upper parts Pinkish-Cinnamon, individual hairs 

 plumbeous at base and finely tipped with black; color purest on sides, 

 flanks, cheeks and top of nmzzle; hairs of cheeks and muzzle, where 

 pigmented, white at base; entire underparts, lower half of cheeks, 

 thighs, dorsal surfaces of hands and feet, tips of ears, and supra- 

 orbital spots, white ; all unpigmented hairs wliite to base ; tail finely 

 covered with white hairs. Tail short and heavy, becoming expanded 

 more or less club-shaped distally and in dry specimens flattened dorso- 

 ventrally ; hind feet small ; ears rather large. 



Measitrements. — An adult female, labeled only Egypt but presum- 

 ably from near Cairo, measured: Total length 165; length of tail 

 55 ; length of hind foot 24 ; occipitonasal length 35.3 ; length of palate 

 15.8; length of palatal foramina 6.4; length of bulla 16.5; crown 

 length of upper molar series 4.4; least interorbital width 6.3. 



Remarks. — This animal superficially resembles Meriones libycus but 

 may be readily distinguished from that species by the short, club- 

 shaped, fatty tail and by a greater extension of the nasals and much 

 larger, more inflated bullae. 



The immature animal lacks the bright color of the adult and appears 

 instead much darker, owing to the greater amount of basal plumbeous 

 and black tipping of the hairs. In the immature skull, the general 

 conformation is the same but minor changes occur as adulthood is 

 reached. The space between the mastoid portions of the auditory 

 bullae is greater in the immature, no supraorbital ridge is developed, 

 the nasals appear to encroach more into the frontals, the interparietal 

 becomes slightly smaller and the wings of the supraoccipital become 

 more defined as the animal ages. 



MERIONES LIBYCUS LIBYCUS Lichtenstein 



Meriones libycus Lichtenstein, Verzeich. Doubl. Zool. Mus. Berlin, 1823, p. 5, 

 No. 9. (Type locality given by Ellerman (1947, p. 485) as near Alexandria, 

 Egypt.) 



Specimens examined. — Thirteen. Giza Province: Suez Road, 

 8 miles east of Heliopolis, 1 ; Suez Road, 5 miles east of Heliopolis, 10. 

 Suez Canal Zone : 3 miles northwest of Fayid, 2. 



