tlie smaller British Mammalia. 275 



It will be seen that the tail was more than half the length 

 of the body : it was also of two colours, as in the A, riparia, 

 dusky above, whitish beneath. The ears were apparent out 

 of the fur ; and the general colours were those of the species 

 just mentioned. 



I will now annex the exact relative measurements of the 

 cranium : — 



lines. 



Entire length 11 



Breadth across zygomatic arches 6^ 



behind the zygomatic arches ... r)^ 



Length of the nasal bones 3 rather exceeding. 



Breadth of the nasal bones 1^ 



of space between orbits If 



Length of the orbit 4 nearly. 



Breadth of the orbit 2^ 



Though much bent, the bones of the zygomatic arches are 

 very slight compared with those of the A. neglecta, or even the 

 A, arvalis. The incisors also are shorter and slenderer. All the 

 molars above and below are deeply stained with a purplish 

 ebony colour, pervading nearly the whole exposed portions of 

 the teeth, except their grinding surfaces. There is only a faint 

 stain of this colour on the molars of the A. neglecta and the 

 A. arvalis. 



Though this cranium appears so dissimilar to that of the 

 A, rubidus of De Selys, as represented in his work, it closely 

 resembles his figure of that of the A. duodecimcostatus ; a spe- 

 cies, however, to which it cannot be referred, inasmuch as the 

 specimen described above had the same number of ribs as the 

 A. arvalis. 



The number of vertebrae I am not able to state, as previous 

 to my having an opportunity of examining its internal struc- 

 ture, the specimen had been deprived of a portion of its tail*. 



I may, however, add" the measurements of the intestinal 

 canal : — 



in. lin. 



Small intestines 14 9 



Caecum 4 9 



Large intestines 8 6 



These measurements will be found very different from those 

 given by Mr. Yarrell ; but as we have already seen how liable 

 to variation these parts are in relative length, and as Mr. Yar- 



* I may just state in explanation, that after examining its external cha- 

 racters in 1889, the specimen was returned to Mr. Thompson, who had it 

 skinned, I imagine, for mounting. The body was afterwards forwarded to 

 me in spirits for dissection, in a mutilated state. 



T2 



