1 900.] MUS SYLVATICUS AND ITS ALLIES. 409 



the Carpathians ; or in the comparatively flat cultivated country at 

 Grageni, at the foot of the Carpathians, north-west of Bucarest. 

 Badde's description of the form found in the Caucasas, the Crimea, 

 and in Western Siberia shows that a band of large sylvaticus-like 

 Mice extends eastwards right into Siberia until in the East they 

 meet the subspecies 21. s. chevrieri; but, in the absence of specimens, 

 it is impossible to lay down the exact relationships of these forms, 

 or to state where one ends or the other begins. A single young 

 specimen from Montenegro seems to belong to M. s. princeps, and, 

 as has been stated above, a set from Haute-Savoie are in certain 

 respects intermediate between this form and 21. s. ivintoni, with 

 which form it must intergrade in various localities. 



General Remarks. 21. s. princeps is undoubtedly a bright East 

 European representative of 21. s. ivintoni. For our knowledge of 

 it we are indebted to the late Mr. W. Dodson, whom, through the 

 liberality of the late Lord Lilford, I was enabled to send on a 

 collecting trip to Boutnania in the spring of 1899. Mr. Dodson 

 brought back a fine series of 44 examples of all ages and sexes, 

 showing that this form occurs in the regions which he visited to 

 the apparent entire exclusion of the smaller forms of Long-tailed 

 Field-mice. 



This Mouse seems to breed in early spring, for amongst Mr. 

 Dodson's specimens is a young one caught on April 15th, 1899, 

 which, although attaining to a head and body length of 87 mm., was 

 still in the slaty-coloured pelage of immaturity. 



9. Mus sylvaticus islandicus. 



21us islandicus, F. A. L. Thienemann, Nat. Bemerk. ges. auf 

 einer Beise im Norden von Europa, p. 153 (1824). 



Type from Iceland ? non existent ; a co-type in Brit. Mus. of 

 Nat. Hist., no. 45.11.15.17, received from Dr. Thienemann. 



Description. " M. cauda corpore aequanti supra e f usco cinereus 

 subtus albus." Seems to be smaller than ordinary 21. sylvaticus. 



Distribution. Iceland. 



General Remarks. It has long been known that small rodents of 

 some sort are found in Iceland, and there have been many discussions 

 as to the exact nature of them. Some naturalists have supposed 

 that they are Lemmings ' ; but it is now certain that some forms 

 both of 21us sylvaticus and of 21us musculus occur in the island. 

 The Bev. H. H. Slater has been good enough to inform me 

 that, while both species occur on the coast, the former is the 

 House-mouse and the only species of the interior. Thienemann's 

 description, although it gives no characters whereby 21. s. islandicus 

 may be distinguished from the Mice of other localities, and although 

 he was himself of the opinion that his Mouse presented some of 

 the characters both of Mus sylvaticus and of Mus musculus, clearly 



1 See the remarks of J. Steenstrup in ' Videnskabelige Meddelelser fra 

 den Naturhistoriske Forening i Kjobenbavn,' pp. 51-00 (1807), translated in 

 the Ann. & Mag. Nat. Hist. ser. 4, iii. pp. 445 &c. (1869). 



