1910.] VARIETIES OF MUS RATTUS IX EGYPT. GoS 



I have .already referred to the fact that in India the three 

 varieties of M. rattvs may roughly be con.sidered as hill, tree, and 

 house forms ; but in Egypt, where the cultivated parts frequented 

 by these rats are low-lying and level plain.s, only two form.s were 

 found. 



I made a number of careful observations in the Gixa Gardens, 

 where both forms are found, to see whether the two varieties were 

 really difterent in their liabits, but such evidence as I was .able 

 to get together wn,s very inconclusive. Large numbers of plane 

 trees grow in the Gardens and on these, often at a considerable 

 heiglit from the ground, many heaps of the fruit, looking not 

 imlike squirrels' dreys, were to be found. These w^ere un- 

 doubtedly brought together by rats, but investigation proved that 

 they were used merely as convenient platforms on which to feed, 

 and not as sleeping or breeding places. The seeds of these trees 

 are apparently a favourite food, and as it would be impossible for 

 a rat to devour them in situ, they are picked and carried to the 

 first convenient spot, generally a fork near the main trunk, to be 

 devoui'ed, and it is on such places that the accumulated debris 

 forms the apparent nests. On the other hand, the fruit which 

 had fallen to the ground was frequently taken into a neighbouring 

 Imsh and eaten there, so that there is undoubtedly a tendency to 

 an arboi-eal life. 



On two occasions only did I actually see a, rat in a tree, and 

 neither time were they accurately identified, although one, I am 

 almost certain, belonged to the white-bellied form {M. tectorvm). 

 Both forms were found living in burrows in the ground as well 

 as in the houses, so that there seems to be but little difference in 

 habits between the two vaiieties. The apparent absence of the 

 third (Indi.an) subgroup, however, taken in correlation with the 

 lack of high ground, seems certainly suggestive, but I sh.all have 

 more to say on this point later. 



In studying the various forms of Mus rattus I found it con- 

 venient to classify them into four groups. 



(i.) The Ti/pical Tectoruin, in which the hairs of the under- 

 parts are white to their ])iiscs and the u[)per sui-face of 

 the hind feet is also white, 

 (ii.) TJie Grei/ Teciomm, in which the hairs of the underparts 

 are white to their bases but the upper surface of the hind 

 feet shows traces of brown. 



(iii.) The Grey Alexandrinus, in which the hairs of the under- 

 parts have slate-coloured bases and the upper surface of 

 the hind feet shows much brown. 



(iv.) TJi.ft Typiccd AlexaJidrinus, in which the hairs of the under- 

 parts are slate-coloured throughout or nearly so, and the 

 hind feet entirely brown on the upper surface. 



In actual shade of colour nuich variation was shown. Groups 

 (iii.) and (iv.) were constantlv d;\i-ker than liroups (i.) ;ind (ii.), 



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