﻿MAMMALS FROM THE NILE DELTA REGION, EGYPT — SETZER 363 



phases the tail is more or less bicolored and the dark doi*sal stripe cor- 

 responds to the back color. In the first phase, the ears are pale, re- 

 sembling the dorsal color ; in the second and third phases the ears are 

 dark, as is the dorsal color. The skulls show no one feature that might 

 tend to segregate any of the above color phases as subspecies. They 

 are all regarded as Mus musculus. 



Measurements. — Averages and extremes of two males and four 

 females from Alexandria, Behera Province, were respectively : Total 

 length 157 (156-158), 166.2 (157-173); length of tail 78 (78), 78.7 

 (74-82) ; length of hind foot 17 (17), 17.3 (17-18) ; length of ear from 

 notch 13 (13), 13.3 (13-14) ; gi-eatest length of skull 21.7 (21.2-22.2), 

 21.7 (21.0-22.4); occipitonasal length 21.2 (20.8-21.6), 21.0 (20.5- 

 21.7); length of palate 10.05 (9.8-10.3), 9.9 (9.6-10.4); length of 

 palatal foramina 5.2 (5.2) , 4.7 (4.5-5.0) ; crown length of upper molar 

 series 3.15 (3.1-3.2), 3.2 (3.0-3.4) ; length of nasals 7.9 (7.8-8.0), 7.8 

 (7.5-8.3) ; least interorbital width 3.55 (3.5-3.6), 3.5 (3.5) ; greatest 

 zygomatic width 11.05 (11.0-11.1), 10.9 (10.6-11.1). 



Remarks, — The names applied to the house mice of the Delta region 

 appear to be in as much confusion as are the names applied to Acomys 

 and to Rattus. It is not thought wise to try to solve the nomen- 

 clatural mix-up on so few specimens. The material available is ex- 

 tremely heterogeneous and shows all the types that have been rec- 

 ognized from the Nile Delta and southward. 



Mus musculus gentilis^ which occurs in a feral condition farther 

 south along the Nile, appears to be the name most applicable to the 

 largest numbers of animals from the Alexandria-Cairo-Suez area. 

 There are, however, individuals that would appear to belong to the 

 north European stock of Mus musculus musculus and Mus musculus 

 domesticus. In addition, there are specimens of a light color phase 

 from Alexandria that do not correspond to any of the named kinds of 

 Mus musculus supposed to be in this area. Cranially, all the speci- 

 mens examined appear to be of one subspecies. 



It is thought best, at this time, merely to refer the house mice of 

 northern Egypt to the species Mus 7nusculus. 



ACOMYS CAHIRINUS (E. Geoff roy St.-Hilaire) 



Mus cahirinus E. Geoffeoy St.-Hilaibe, Catalogue des mammifdres du Museum 

 National d'Histoire Naturelle, p. 195, 1803 (Cairo, Egjrpt). 



/Specimens examined. — Thirty. Behera Province: Alexandria, 8. 

 Daqahlia Province: 5 miles west of Simbillawein, 1. Giza Province: 

 Cairo, Abassia Fever Hospital, 5; Abu Eauwash, 2 (MVZ) ; Cairo, 

 4; Kafr Taharmes, 1; Saket Meki, 2. Suez Canal Zone: Suez, 6. 

 Nubia: Abu Simbel, 1 (MVZ). 



