780 Quadrupeds. 



is food, there will be provided that which feeds on it, and that in just 

 proportion. I would not be tedious to your readers, but perhaps they 

 will allow me to adduce an illustration of this principle, in connexion 

 with the little creature of which I am writing. 



The mole is evidently an appointed check to the undue increase of 

 the earthworm : it not only devours numbers itself, but by its bur- 

 rowing drives to the surface many more, which, in their attempt to 

 escape the mole, fall a prey to the robin and the thrush. The earth- 

 worm, unquestionably, has its uses, in drawing vegetable substances 

 beneath the surface, and so the gases that are released in the process 

 of decomposition, and which would otherwise be lost, are preserved 

 for the nutriment of the growing plant, while the portion devoured by 

 the worm is again thrown to the surface in the form best adapted 

 for the nutriment of the plant above ground. But worms devour the 

 roots of plants ; and were there no checks to their increase, vegeta- 

 tion would be seriously injured, instead of benefited, by their exist- 

 ence : so long, however, as they are kept in check by the mole 

 beneath, and the birds above ground, perhaps even their destruction 

 of some plants is beneficial in preventing a too crowded herbage. 

 Thus, then, all is well arranged by Divine wisdom ; but if man steps 

 in, throttles the mole, and shoots or snares the birds, he must, if he 

 carry his interference far, produce a disturbance among God's works, 

 to his own detriment. 



Common Shrew is common enough ; in proof whereof I may men- 

 tion, that Mr. Gray, suspecting, as do some other naturalists, the 

 existence of more species in this country than have as yet been de- 

 scribed, wished me to procure him a number of specimens for com- 

 parison ; and I had no difficulty in collecting eight in a very few 

 days. These I forwarded ; and Mr. Gray's reply, wherein, while 

 deciding that they all belonged to the common species, he points out 

 the sexual distinctions, may prove interesting to your readers : "The 

 males (of which there are five), like many other insectivorous and 

 marsupial quadrupeds, have much thicker and more hairy tails than 

 the females. The hair of the tail is brown, and forms a pencil at the 

 end ; and the whole tail is brown, from the colour of the hair. The 

 females have the teats, three in number, forming a line along the groin 

 on each side. Their tails are cylindrical, slender, and white, from 

 the shortness and spareness of the hairs allowing the skin to be seen 

 between them, and have no terminal pencil." I can throw no light 

 on the autumnal mortality among the shrews. 



The Water Shrew I cannot establish ; and yet I have frequently 

 tracked on the mud by the river-side (during winter, when there could 



