THE DORMOUSE OR SLEEPER 



361 



Oeographical variation: — As shown by the Italian and Sicilian 

 forms, pukher and speciosus, there is evidently a tendency to brighter 

 tints and more striking contrasts in the south. In 1900 (see Synonymy), 

 I separated the British form from M. a. avellanarius on the ground that, 

 whereas each is more dully coloured than M. pulcher, the British, which 

 I named M. a. anglicus, appears to have the upper side more brilliant, 

 a whiter breast, and a thicker and shorter tail than the typical form. 

 Miller, working more recently, is unable to accept this conclusion ; but 

 there is room for further study, as no series of British dormice is available 

 for examination. 



DIMENSIONS IN MILLIMETRES:— 



Skull: — Greatest length, 22-7 to 24-5 ; condylo-basal length, 21-8 to 

 23 ; breadth at zygomata, 13-2 to 14-4 ; inter-orbital breadth, 3-0 to 3-4 ; 

 mastoid breadth, 1 1 ; depth of brain-case at middle, 8-0 ; greatest length 

 of nasals, 6-8 to 7-2 ; of diastema, 6 to 6-2 ; of mandible, 13 to 14 ; of 

 maxillary tooth-row, 4-8 ; of mandibular tooth-row, 4-2 to 4-4. 



Weight in grammes: — Rabus (Zoo/. Garten, 1881, 321-325, trans- 

 lated in Zoologist, 1882, 161-164) found that this varies between 23 and 

 43. It increases during the season of activity, especially in September, 

 and attains its maximum just before the commencement of hibernation. 

 It then decreases,^ a female having dropped from 37 to 26 during 

 hibernation lasting from 19th October to 27th March, or about at 

 the rate of 2 a month. The September increment amounted in 



■ Some naturalists have curiously supposed that both fat and weight increase 

 during hibernation. 



VOL. II, 2 A 



