as Eneniies of Mankind. 



3 



colonies of mixed origin ; nevertheless, since each has a certain 

 geographical value of its own, and since each may breed true to 

 its type, it is not only convenient but natural to regard each as a 

 distinct sub-species. These sub-species may be defined as 

 follows : — 



1. Battles rattus rattus. The Black Eat. 



Back black ; belly smoky grey. Fur on back long and rather 

 harsh ; on belly short, sleek, and adpressed. (This, technically the 

 type of the species, is essentially characteristic of the cold 

 temperate countries of Europe.) 



2. Rattus rattus alexandrinus. The Alexandrine Eat. 



Back brownish grey ; belly more or less dingy ; dorsal and 

 ventral colours merging insensibly in each other on flanks. Fur 

 usually rather harsh on back ; on belly usually longer and 

 rougher than in B. r. rattus. (Essentially characteristic of Asia 

 Minor and North Africa.) 



3. Battiis rattus frugivorus (" tectorttm"). The Eoof Eat or Tree 



Eat. 



Back yellowish or reddish brown ; belly pure white or pale 

 lemon ; dorsal and ventral tints separated on flanks by a sharp 

 line of demarcation. Fur very soft and full, with few bristles ; 

 particularly long and dense on belly. (Essentially a wild-living 

 rat, inhabiting Sicily, Italy, Spain, and the Mediterranean region 

 generally.) 



All these forms have been conveyed by human commerce to 

 the various ports of the world. Where they have not had to 

 compete with native races of B. rattus, or with the more formidable 

 B. norvegicus, and have met with suitable climatic conditions, they 

 have frequently established a strong foothold and have colonised 

 large tracts of the interior. 



All forms of B. rattus, whatever may be their colour, seem to 

 have descended from a bright coloured, soft furred stock, closely 

 resembling B. r. frugivorus. Such rats, differentiated into many 

 local sub-species, abound in India and Burma, and there can be 

 little doubt that these countries were the cradle of the species ; 

 there, as in the Mediterranean islands, the white-bellied races are 

 frequently found living a wild, more or less arboreal, life in the 

 open country, far away from all human habitations. 



