440 MURIDA:—AGRESTIS 
requires further investigation. J/. a. xeglectus probably occurs on the 
coastal islands, having been taken by Sheppard on Bute (see Pvoc. 
Zool. Soc., London, 1913, 833), where it occupies marshy ground south 
of Kilchattan, and the road-sides in the extreme south of the island. 
Distribution in time :—According to Hinton, JZ. a. neglectus, or a 
similar form, appears first in the late pleistocene Fauna of Ightham 
Fissure, Kent, while J7. zr/us is only known in more recent times. 
Description :—This Grass Mouse is as large! as its relatives of the 
islands, differing from exsz/ chiefly in having, on the average, a simpler 
mu; besides being much larger than JZ. hzrtus of England it is more 
heavily furred, and has the upper surface darker and browner. The 
light bars of the hairs are near ‘“‘ochraceous buff” approaching tawny, 
and the resulting colour of the pelage is near “prouts brown,” with 
suggestions of “burnt umber” and “raw umber”; the under-side 
is some shade of dull grey, or may be lightly washed with yellowish or 
“wood brown.” A male taken by Sheppard on 24th July 1908, 
was moulting. 
The skull of young adult and middle-aged specimens is larger than 
that of AZ. hirtus, having a condylo-basal length of 25-4 to 26.6 mm. 
At this stage it resembles that of JZ. a. evsul of similar size, but has 
smaller bulla, as in JZ. /zrtus. In old age it attains a condylo-basal 
length of from 27-5 to 28-1 mm. or more, and the distinction from 
M. a. exsul in respect of the bullz is less striking. 
The teeth are of the normal form; 7’ is usually without any trace 
of the fourth inner angle, but occasionally a vestige of it is present in 
the larger specimens; it never attains the size sometimes attained 
in exsud. 
Dimensions in millimetres:—Immature female, 109 —37—18—13; 
subadult male, 118—42—17-5—12; old male, 128—40—19—16. 
Skull :—Condylo-basal length, 25-4 to 28-1 ; breadth, zygomatic, 14-4 
to 16-1; inter-orbital, 3-2 to 3-6; occipital, 11-2 to 12-8; depth, median 
occipital, 6-2 to 6-9; length of nasals, 7 to 8-1; of diastema, 7-2 to 8; 
of mandible, 16 to 17-5; of maxillary tooth-row, 6-5 to 7; of 
mandibular tooth-row, 6-2 to 6-5. 
Status :—J/. a. neglectus is a little less primitive than the Hebridean 
exsul in that its 7! is slightly more reduced; like evsw/ and the other 
British sub-species, it is, however, intimately related to the true agrestis 
of Skandinavia. The differences between them appear mainly to be 
due to a long-continued segregation. The close relationship of these 
North British and Skandinavian forms is parallel to that of the Varying 
Hares, of which Lepus timidus scoticus agrees closely with ZL. ¢. temidus 
of Skandinavia; but there are no Irish Grass Mice to repeat the 
relationship between Z. Azbernzcus and the extinct pleistocene L. anglicus. 
1 Miller and other writers never examined full-grown specimens. 
