130 ANNALS OF SCOTTISH NATURAL HISTORY 



imperceptibly through the flanks to the peppery reddish-brown of 

 the upper surface. 



All these peculiarities seemed to clearly point to a new species 

 or subspecies of Mouse ; but, the animal having been in spirit, its 

 colour was regarded as unsatisfactory, and the unusual proportions 

 of its ears and tail were ascribed to individual variation. And so 

 the specimen was put on one side in the hope that in due time 

 further examples might be procured. 



Early in the spring of the present year I happened to come 

 across the specimen, and, being greatly struck by its remarkable 

 appearance, I at once endeavoured to procure some more of these 

 St. Kilda Mice, with the result that my friend Mr. Henry Evans, 

 during the course of a yachting cruise, put in at St. Kilda and landed 

 some traps for me. Thanks to Mr. Evans, I have now before me, 

 in addition to Mr. Steele Elliott's specimen, a fine adult pair, male 

 and female, as well as a young female, of the St. Kilda Mouse. 



The dimensions, in millimetres, of these St. Kilda Mice are as 

 follows : 



Head ^ , Hind p 



and body. foot. 



(J (skin: ]. Steele Elliott, 1894) . 81 85 25 



g ( ,, H. Evans, 1898) . . 107 91 24.5 17 



? (spirit: ,, ). . . HO 94 24 15 



? ( juv. ). 82 77 24.5 15.5 



They are thus remarkably large Mice for typical Mtis sylvaticus, 

 and the adults equal in size the largest measurements of the form 

 known as Mus flavicollis^ Melchior. The skull of the adult male is 

 as large an example as I have ever seen, reaching a total length of 

 29 mm. 



The following list of total lengths of the skulls of various 

 sylvaticus^ks. forms will illustrate this point : 



mm. 



M.flavicollis? $ . . . . 29 Suffolk. 



,, ^ .... 28 Hereford. 



c? .... 27 

 $ .... 28 

 . .28 



M. hebridensis, (type) . . . 27 

 M. sylvaticus (old) .... 26 



,, (in general) . . . 26 to 27. 



In form and proportions these Mice resemble Mus hebridensis, the 

 form of slyvaticus described by my friend Mr. W. E. de Winton from 

 the Isle of Lewis, Outer Hebrides (" Zoologist," Oct. 1895, P- 3^9)- 

 The adult female from St. Kilda (which is in spirit) may possibly 



1 The majority of these specimens have been placed at my disposal by my 

 friend Mr. De Winton, 



