ON THE IDENTITY OF THE IRISH RAT. 7 



that the whole list would be too long for insertion here in its 

 entirety, and that a condensed summary would be sufficient. 

 Negative evidence has been considered of little value, as it is 

 thought that the presence of Mus hibernicus in a district or 

 locality has been frequently overlooked. Indeed, both positive 

 and negative evidence has sometimes been received from the 

 same locality. 



Positive evidence (in some cases of more or less doubtful 

 value) has been received of the presence of Black Rats in 

 seventeen Irish counties. These, with the exception of the 

 Queen's County, are all situated on or near the coast, but chiefly 

 on the eastern side of the island. Some reputed localities are, 

 however, in the extreme west : thus all Ireland, except the most 

 central parts, is included in the list of localities. It has been 

 found that those counties (such as Armagh, Antrim, and Wex- 

 ford) which have been most closely examined, have produced the 

 most successful results, although they are situated in widely 

 separated parts of Ireland. It is our belief that, when all Ireland 

 has been as carefully examined, Mus hibernicus will be found to 

 exist in varying abundance, though, perhaps, locally, all over the 

 island. The localities from which specimens have been received, 

 either by Thompson or by ourselves, are twenty in number, and 

 are distributed over the following counties : — Antrim (2), 

 Armagh (2), Carlow (2), Dublin (2), Kilkenny (1), and Wexford 

 (11). These counties all lie on the east coast of Ireland, and 

 were an attempt made to estimate the distribution of Mus 

 hibernicus from them alone, we should have to conclude that the 

 animal is confined to the extreme east. Yet an examination of 

 the evidence received from the west coast (which is unfortunately 

 of too great length to be given here) shows that its presence 

 the there is at all events extremely probable. It is likely that 

 head-quarters of the Black Bat in Ireland are now in Carlow, 

 in one part of which (Fenagh) it is said even to equal the Brown 

 Rat in numbers. But its abundance appears to vary very con- 

 siderably in different localities, and even in the same locality at 

 different times. Thus at Ballyhyland (Wexford) it was common 

 in 1872, after which it became scarce, and disappeared altogether 

 after 1878, from which date no Black Rats were observed until 

 August, 1889, when a specimen was trapped and forwarded to us 

 by Mr. C. B. Moffat. At Fenagh (Carlow), on the contrary, it 



