418 Rev. L. Jenyns on the British Shrews. 



naturalists who interest themselves with our native Fauna, and 

 who may wish to know what our present knowledge of the 

 species of this puzzling group amounts to. 



The square-tailed shrew, by which name I designate the 

 larger of the two species above alluded to, differs from the 

 common shrew of English authors, not only in its superior size, 

 but in the characters of the snout, feet, and tail, and to a less 

 extent in the dentition and colours. It maybe thought that some 

 of these characters are not to be depended on after what I my- 

 self have stated on this subject in a former paper. But it 

 must be remembered that, though variable, the variations are 

 in some measure due to age ; and that, if we can obtain indi- 

 viduals of different ages, we may at once know what allowance 

 to make for this circumstance. Also, although the same cha- 

 racter may in some cases vary in different individuals of the 

 same age, yet it still varies within limits, and by examining a 

 number of specimens we may obtain an average which will 

 be tolerably constant in a given species. Thus with regard to 

 the relative size of these two species, I find the average length 

 of the square-tailed shrew (measured from the extremity of the 

 snout to the anus) to be about two inches and three quarters, 

 individuals being occasionally met with that exceed three 

 inches ; whereas the average length of the common shrew is 

 hardly two inches and a half, nor did I ever meet with a spe- 

 cimen that was more than two inches and eight lines. Hence 

 the maximum size attained by the latter species is hardly equal 

 to the average size of the former. The characters of the snout 

 depend in some measure upon age. I have noticed in my 

 former paper, that this part is more attenuated in old than in 

 young specimens ; at least it appears so, from the circumstance 

 of its not increasing much in breadth as the animal grows. 

 But it will be at once manifest, on comparing individuals of 

 the same size, that in the square-tailed shrew the snout is much 

 broader, more swollen at the sides, and more obtuse at the 

 extremity than in the common shrew. In the former species 

 the distance between the eyes is contained barely once and a 

 half in the distance from the eyes to the end of the snout. In 

 the latter it is contained twice in the same. The feet are also 

 obviously different in the two species. Those of the square- 



