728 RODENTIA—MURIDZ 
castaneus, but its colour pattern is modified somewhat so as to make 
an approach towards that of S. gvantzz. 
Neomys fodiens bicolor (Shaw). 
From Skye we received five specimens collected in June and July 
by Mr C. H. B. Grant. These differ in no way from the Water Shrew 
of the mainland. 
RODENTIA. ; : 
MURIDA. 
THE FOULA FIELD MOUSE. 
APODEMUS FRIDARIENSIS THULEO, Hinton. 

1919. APODEMUS FRIDARIENSIS THULEO, M. A. C. Hinton, Scottish Naturalist, 
November and December 1919, p. 177, described from the Island of Foula ; type, 
an adult female, collected November 1917 (original No. 5.). 
tgs Gi ty eas wed 
Distribution :—Foula (the Ultima Thule of Tacitus). 
Description :—In general external appearance this animal closely 
resembles typical /7zdarzenszs, but differs in its smaller size and larger 
hind-feet. 
Size small, the head and body measurement being scarcely greater 
than in A. sylvaticus, and therefore considerably less than in A. f 
fridartensts. The tail is about equal to the head and body in length 
when all the specimens in adult pelage are averaged; but it is slightly 
shorter relatively in the larger or older specimens. The hind-foot 
is very large, its absolute size being as great asin the St Kilda Field 
Mouse, A. Azrtensis, while its relative size is larger than in any other 
British form, The sole-pads are small as in typical frzdarzensis. 
In colour the Foula Field Mouse agrees exactly with typical 
fridariensts. The flanks are dark, the lateral line of demarcation 
being regular and ‘sharply defined. The ventral surface is of a 
dull bluish white, without any trace of a buffy suffusion. Normally 
there is no trace of a pectoral spot. The tail is strongly bicoloured, 
dusky above, white below. Dorsal surfaces of the feet white. 
A direct comparison of the skulls suggests a closer affinity between 
A. f. thuleo and A. f. granti than between the former and true 
fridariensts. The bull are as small, and the masseteric plate projects 
as little anteriorly as in grantz’; while the brain-case appears to be 
still broader, rounder and more depressed than in the latter sub-species. 
In the mandible the coronoid process is very feebly developed as in 
