THE COMMON GRASS MOUSE 445 
The skull resembles that of J/. a. ervsu/, but is smaller and has 
relatively smaller bulle. 
The teeth are quite like those of normal agres¢zs, m! being without 
a small fourth inner angle. 
Exceptional variation:— White varieties are not common, but 
there are a number of records of specimens exhibiting various degrees 
of albinism, a few quite white with pink eyes, the rest in intermediate 
conditions from cream to piebald. A black variety was recorded by 
Southwell (Zoologist, 1890, 216). 
DIMENSIONS IN MILLIMETRES :— 
Nl 


Tail (with- | Hind foot Ear ase 
hae and |outterminal| (without | (greatest Seaton | 
y- hairs). claws). length). | © ae | 

SPECIMENS FROM REIGATE, SURREY, CAUGHT AND MEASURED BY L. E. ADAMS. 
SexuaLLy IMMATURE OF BoTH SEXES :— 

1. 19th May 1912, average of 5 fotuses 
ready for birth . A 3 : 34 
2. 17th July 1912, average of 4 in upabs 
umbilical cord still showing . 40 12 9 4 3 
8. 10th July 1912, average of 6 in nest; 
slight gown on back ; umbilical cord 
showingon2 . 45 12 9 5 35 
4. 15th June 1912, average ‘of 7 in nest ; 
furred above and very slightly below; 
eyes and ears closed. : . 46 12°5 10 5 3:5 
. 15th June 1912, average of 7 in nest; 
completely furred, ears closed: eyes 
o 
opening . 54 14 12 5 45 
6. 9th July 1912, average of 4 in nest $ 
completely furred, Byes and ears closed 56 15 13 65 55 
7. Male, 11th July 1912 = eyes and ears 
open 56 17 15 7 5:5 
8. Female, 30th May 1911; ; juy enal pelage 5 
vagina perforate 78 24 15 11 12 
9. Male, Ist June 1911; juvenal pelage . 78 28 16 11 12% 
10. Male, ® 28th Sept. 1912; juvenal pelage . 81 29 16 10 162 
11. Female, 30th Oct. 1911; adult pelage . 82 30 16 10 155 
12. Male, 9th Oct. 1912; adult pelage - 83 29 16 10°5 164 
18. Male, 31st Oct. 1911; adult pelage 6 $3 34 7 10 145 
14. Female, 28th Sept. 1912; adult pelage . 85 28 17 10 168 

SEXUALLY MatuRE MALEs :— 











1. 26th May 1911 s x : F 104 38 16°5 12 31 
2. 2nd June 1911 c é O é 108 46 18 12 28°5 
3. 2nd June 1911 R . . > 100 35 16 11 | 24 
4. 10th Junel191l_. . : j 96 32 16 11 23 
5. 11thJunel9ll_s. A a 5 101 35 17 11 31 
6. 11th June 1911 = ° 5 . 110 39 16 11 29 
7. 17th June 1911 115 34 16°5 abi 25 
8. 10th July 1911 Cargest ever measured 
by Adams) 5 a 118 40 17 11 30 
9. 15th July 1911 a 2 . . 87 32 15 11 19 
10. 30th Oct. 1911 B 5 5 é 101 38 18 11 24 
11. 6th Noy. 1911 : o ‘ Q 96 38 17 11 21 
12. 14th May 1912 5 A : > 99 32 16 12 32 
13. 14th May 1912 . 2 . : 10+ 38 17 12 34 
14. 15th May 1912. : 4 - 98 36 17 11 25 
15. 16th May 1912 ' 5 A : 89 3 17 11 19 
16. 17th May 1912 . A : : 104 36 16 11 33 
17. 18th May 1912 . . 5 2 103 34 16 12 32 
18. 18th May 1912 5 A a c 101 33 17 12 34 
19. 19th May 1912 . : : ° 95 35 18 11 25 
20. 2ist May 1912 : . . . 108 31 17 12 28 
Average 5 . 5 101° 36 16°7 11°8 27-4 
1 Testis 2 mm. in diameter. * Testis 1 mm. in diameter. ® Imperforate. 
4 Testis 1 mm. in diameter. 5 Testis 2 mm. in diameter. ® Imperforate. 
VOL. II. 2 F 
