84 MAMMALS. 



Mus musculus, L. Common House Mouse. 



Abundant everywhere. In a note by the late E. Heddle, one 

 of the authors of the Hist. Nat. Ore., it is stated that the 

 "Button Mouse " mentioned in a foot-note at p. 15 of the above 

 work, " is the young of Mus musculus, the colour heightened by 

 open-air life. E. EL, 1856." 



In the Northern Ensign of May 1857 it is recorded that no 

 less than three thousand four hundred and ten mice were killed 

 on the farm of Husbay in Stronsay, in a few days, while 

 thrashing out some stacks, besides what were destroyed by dogs 

 or escaped. 



Mus rattus, L. Black Rat. 



In the old Statistical Account for 1793, vol. vii. p. 546, it is said 

 that the " Black Muscovy Eat, which is the only one now to be 

 met with (in Orkney), has destroyed the Grey or Brown Eat." 

 This seems to be reversing the general order of things. 



In Baikie and Heddle's time the Black Eat was said to be 

 confined to the island of S. Eonaldsay, and was even then 

 (1848) decreasing fast, thus corroborating Low's statement. 

 Mr. Eanken, writing in 1889, says that the last Black Eat he 

 heard of, was killed by a horse treading on it in a stable, at 

 Osquil (?), in the winter of 1877-8. Unfortunately a cat had 

 gone off with the remains, so that Mr. Eanken was unable to 

 verify this instance. 



Mr. Moodie-Heddle says the Black Eat is getting rare, but 

 is still to be found in S. Eonaldsay ; we have not had as yet 

 any opportunity of personally verifying the latter statement. 



Mus decuman us, Pall. Brown Rat. 



Orkney does not seem to be altogether the happy hunting-ground 

 of the common rat, as he has a habit, unhappily unknown on 

 the mainland or others of the British Isles, of dying out of some 

 of these islands. Thus rats, which were introduced into Eousay, 

 left somewhere about 1836, according to Baikie and Heddle, 

 and were unknown there in 1883, when Buckley was there. And, 



