204 THE ZOOLOGIST. 



body, 9 in. Tail, 7j in. (generally thicker at the base, and 

 shorter than in the other subspecies). Hind foot, 35 mm. 



This is apparently a recent arrival in England ; the true type 

 as described above appears to have reached both Scotland and 

 Ireland. It is most commonly found inhabiting the coast ports 

 on the east and south of England, and is very numerous on 

 board ships trading in Southern Europe. Of its original home 

 we are uncertain, but the supposition that it is an eastern form 

 is probably well founded. 



Subspecies 2. — The Northern Alexandrine Eat 

 (Mus rattus rattus). 



This, the most common type, has always been known as the 

 " Old English " Black Rat. Early in the last century it was 

 abundant nearly all over the United Kingdom, but is now be- 

 coming scarce and very local. It has been erroneously called 

 the indigenous type, but there is little doubt that it arrived 

 from the east, probably from Western or Central Asia (possibly 

 Western Mongolia) by way of Russia and Germany, or on board 

 ships from the Black Sea ports. 



In colour the name "Black" Rat is a misnomer for this 

 northern race, as it is not, properly speaking, black.* The upper 

 surface is greyish black or brown, interspersed (behind the 

 shoulders) with glossy white hairs, and the whole upper and lower 

 parts have a blue-grey or purple in them when viewed in the 

 light. The under fur, which is sparse, is pure grey. The ventral 

 surface and limbs are slaty grey. These slate-coloured hairs be- 

 come thin on the upper surface of the feet and toes ; the soles are 

 naked and yellowish ; the toes small and bone-coloured. The 

 tail is ornamented with scales which form rings from root to end, 

 and is covered with short black hairs ; the ears are large, naked, 

 and well rounded : the eyes black and prominent ; the vibrissa 

 fairly numerous, long, and black in colour. Average length of 

 head and body, 7 in. A very large male from Yarmouth now 

 before me measures 8|- in. ; tail, 9 in. ; hind foot, 35 mm. 



* Linnaeus did not call it black ; he speaks of it as " corpore fusco," and 

 otherwise refers to its dusky colour. Pennant probably gave the superficial 

 name of " Black," which has remained ever since. " Blue " would have been 

 more appropriate. 



