408 MB. G. E. H. BARRETT-HAMILTON ON [-^P r - «*> 



Berlin Museum from Riigen. Lastly, a set of eight males and 

 three females collected by Mons. A. Robert at Lueinges, Haute- 

 S;ivoie, in "December 1899, at an altitude of 1100 metres, although, 

 perhaps, slightly smaller and darker than the largest M. s. wintoni, 

 and with the chest-spot less strongly developed, agree so closely 

 with this form in the length of tail, coloration of the underparts, 

 and general appearance, that I prefer to unite them with it, at 

 least provisionally. This form doubtless occurs also in numerous 

 other localities. 



General Remarks. It cannot be denied that the treatment of 

 M. s. wintoni at first presented a good many difficulties, at least 

 as long as we knew it only from isolated localities. It seemed 

 impossible that a large and small form of Mm sylvaticus could 

 occur intermingled throughout the same area without interbreeding. 

 Despite the assertion of Mr. de Winton, who has had such ex- 

 ceptional opportunities of studying these mice in Herefordshire, 

 that the two forms keep quite separate, breed true, and show no 

 intermediates, I was for a long time inclined to treat them as two 

 parallel forms of one dimorphic animal. Even after colonies had 

 been found on the Continent the difficulty remained, and was 

 not dispelled until I had had the opportunity of working out a 

 collection of small mammals taken by the late Mr. W. Dodson in 

 Eournania, and which contained a fine series of the local form of 

 Mus sylvaticus of all ages. These all proved to be very different 

 from M. s. typicus, and are a bright Eastern representative of 

 M. wintoni, which I have now no hesitation in regarding as 

 the "Western sporadic representative of the large East European 

 Field-mouse (M. s. princeps). 



8. Mus sylvaticus princeps, subsp. nov. (Plate XXV. fig. 1.) 



Mus sylvaticus var. jlavicollis, auctorum. 



Type. Original no. 25, a female, Bustenari, Eoumania, 13th 

 April, 1899, collector the late W. Dodson : caught at foot of dead 

 stump in oak-forest. 



Distinguishing Characteristics. An extremely large Mouse ap- 

 parently identical in size and proportions with M. s. wintoni, but 

 adults are eveu brighter red in colour above and purer white on 

 the underside. Many examples possess a breast-spot or band, but 

 this character is not universal, and the band is not so extensive as 

 in M. s. wintoni. Immature specimens are very blue, and re- 

 semble the young of M. s. draco ; they frequently retain the dark 

 colour of the upperside until they are fully as large as adults of 

 M. s. typicus. 



Skull. A large massive edition of that of M. s. typicus, reaching 

 a total length of from 27 to nearly 30 mm. 



Distribution. This was the only Long- tailed Field-mouse obtained 

 by W. Dodson in Eoumania, whether in ihe beech aud oak forests 

 of Bustenari, in the Carpathians N.W. of Bucarest, at a height of 

 480 metres ; at Comana, south of Bucarest : under brushwood on a 

 high plateau near Breba, a large and highly cultivated valley amongst 



