THE ST KILDA HOUSE MOUSE 663 
buff or buffy white, this colour being clearly separated from that of the 
upper surface by a well-marked line of demarcation. 
ant. ant. 

@) 
FIG, 95.—DIAGRAM OF PALATE OF Mus muralis (1), AND Mus musculus (2). 
The skull is slightly larger than is usual in mzsculus, and the 
mesopterygoid fossa (Fig. 95) is greatly narrowed in front, the ptery- 
goids converging anteriorly instead of being approximately parallel. 
This character, less marked in young skulls than in adults, appears to 
be quite constant in murals, and it has not yet been observed among 
the large number of European skulls of musculus examined. The 
teeth do not differ from those of musculus. 
DIMENSIONS IN MILLIMETRES OF % MURALIS AND F4ZROENSIS :— 





Tail F 
c Ear Hind foot 
re a fein (greatest | (without 
hairs). length). claws). 
Mus muralis. 
1. 1898. Female (B.M. 8.7.16.1; type), 
collected by H. Evans . e A 90 85 17 14 
2. Average of 6 females (from spirit), 
on which original descriptions were 
based (Barrett-Hamilton, Ann. 
Scott. Nat. Hist., 1906, 2). 5 5 85-1 815 16°5 12°9 
June 1905. Collected by J. Waterston, 
and described by Barrett-Hamilton, 
op. cit.— 
3. Male 87 81 17 12°5 
4. Female cS c ° 6 c 93 89 18 14°5 
5. Do. S 5 5 eC . c 96 92 18 13 
6. Average of 9 adults, 3 male and 6 
female, collected by Waterston . 84°6 81-4 17-4 13°16 
Sept.-Oct. 1910 and 1911. Collected and 
described by W. Eagle Clarke, Ann. 
Scott. Nat. Hist., 1914, 1271 
7. Male (largest) : . 104°5 74 16°7 13 
Gh dbee aS G . is D . = 108 95°6 18°5 14 
9. Do. (smallest) . 5 c 2 94 81 17 14 
10. Averageof12 males . : : : 99°3 83°4 18°5 14 
11. Female (largest). oC = : : 111 90°5 20 16 
UPR ADs : 5 : . ‘ 5 105 87 19 14 
13. Do. (smallest) . * . : 94 775 19 14 
14. Average of 17 females . . 2 101°4 819 18°3 14°6 
Mus feroensis. 
1. Male (Eagle Clarke, Proc. Roy. Phys. 
Soc., Edinburgh, xv., 164) . ° 7 95°5 96°4 20:2 13°5 
2. Female (type) (Eagle Clarke, Proc. 
Roy. Phys. Soc., Edinburgh, xv., 164 ) 103 95 21 14 
3. Male (Miller, Catalogue, 875) e e 85 97 20 13 





1 Specimens with head and body 90 mm. or less excluded as immature. 
