940 MR. I. G. S. MONTAGU ON A COLLECTION OF 



made here to define them in conformity with the present estimate 

 of their position. An exception is, however, made in the case of 

 M. a. fiona of Gigha since the material representing it is new 

 and undescribed. It is farther considered advisable to indicate 

 the lines along which the projected new groupings will be 

 efiected. 



Group 1. 



Temporal shield type 1. 



M. a. macgillivrcdi. Islay. 



Far colour peculiar ; palate type 1 ; 4th i. a. distinct. 

 M. a. e.vsul. Jura. 



Fur colour typical ; palate type 1 ; 4th i. a. distinct 

 or vestigial. 



Intermediate Grou]). 



Temporal shield intermediate type. 

 M. a. fiona. Gigha. 



Fur colour peculiar ; palate type 2 ; 4tli i. a. vestigial ; 

 jugal peculiar. 

 Group 3. 



Temporal shield type 3. 

 Division 1 . Palate type 1 . 

 M. a. mial. Eigg. 



Fur colour peculiar : 4th i. a. distinct. 

 M. a. exsul. IST. Uist, S. Uist. 



Fur colour typical ; 4th i. a. distinct. 

 M. a. exsul. Mull. 



Fur colour typical ; 4th i. a. distinct or vestigial. 

 Mixed Division. Palates of both types. 

 M. a. neglectus. Mainland. 



Fur colour typical ; 4th i. a. distinct, vestigia], or absent. 

 Division 3. Palate type 2. 

 M. a. neglecttis. Bute. 



Fur colour typical ; 4th i. a. distinct, vestigial, or absent. 

 M. a. exsul. Arran. 



Fur colour typical; 4th i. a. distinct or vestigial. 

 M. a. luch. Muck. 



Fur colour peculiar; 4th i. a. distinct, vestigial, or absent. 



MiCROTUS AGRESTIS FIONA, Subsp. n. 



Microtus agrestis exsul Barrett-Hamilton & Hinton, P. Z. S. 

 1913, p. 830 (1). 



Habitat. Gigha. 



Material examined and Dimensions. One adult ( J ) collected by 

 Sheppard in May 1912, sis adults (3 J" , 3 $ ) and two immature 

 specimens (1 J , 1 $ ) collected by Hancock and Hutchinson in 

 June and July 1922. 



