27 



MURIDAE. 



41. Mus rattus, Linnaeus. 



Black Rat. 



Scot, Ratton, Rotten (common to next species). Ore, Blue Rat. 



Gael., Radan (common to next species). 



Appears to be almost extinct as a native species, although ex- 

 amples sometimes occur near sea-ports; thus Mr. J. M. Campbell 

 lately showed me a fine specimen which was killed on a wharf at 

 Glasgow in 1874. The Rev. G. Gordon, who recorded the existence 

 of the Black Rat in Morayshire in 1844 (Zoologist, 1844, p. 424), 

 informs me that it is now quite extinct there; but it is stated by 

 Mr. H. Stewart to be still found in Wigtownshire (Field, 23rd Aug. , 

 1879). In 1848 the Black Rat was confined in Orkney to South 

 Ronaldshay, as recorded both by Baikie and Heddle (Hist. Nat. 

 Ore, p. 15), and by Wolley (Zoologist, 1849, p. 2344); and it 

 appears to have been owing to this that a belief became prevalent 

 that the Hamster (Cricetus frumentarius, Pallas) had become 

 naturalised in that island (Hist. Nat. Ore, p. 16). In investigat- 

 ing the rano-e of the Black Rat it must be remembered that the 

 black variety of the Water Yole is very often confused with Mus 

 rattus. 



42. Mus decumanus, P alias. 



Brown Rat. 



Scot, and Gael, (see last species). 



Seems to have invaded the south of Scotland from England 

 about the middle of the last century, first appearing in Selkirk- 

 shire between 1770 and 1777 (Xew Stat. Ace. Peeblessh., p. 136). 

 In Morayshire the Rev. G. Gordon says that Brown Rats arrived 

 at the sea-ports about 1814 (Zoologist, 1844, p. 424). In Orkney, 

 Baikie and Heddle state that they have become very numerous, 

 but in Rousay they suddenly died out about 1836, and there were 

 none in 1848 in Enhallow or in Damsay (Hist. Nat. Ore., p. 15). 

 They were introduced into Mull from a wrecked vessel, and were 

 at first treated as pets by the inhabitants. The species is now uni- 

 versally distributed both on the mainland and in the Islands, 

 beino 1 found even on uninhabited islets in the Sound of Harris, 

 where they feed principally on molluscs. 



