206 THE BOOK OF NATURE STUDY 



other things which can only be done on the spot. u Devouring 

 the earth as they make their holes, which are often 4 or even 

 6 feet deep ; bruising the particles in their gizzards, and thus 

 liberating the minute elements of the soil, burying leaves and 

 devouring them at leisure ; preparing the way by their burrowing 

 for plant roots and raindrops, and gradually covering the surface 

 with their castings, worms have, in the history of the habit- 

 able earth, been most important factors in progress. Ploughers 

 before the plough, they have made the earth fruitful/' l Darwin 

 showed that in garden ground there are often 53,000 in an acre, 

 that they pass through their bodies ten tons per acre per annum, 

 and that they bring up mould to the surface at the rate of 3 inches 

 thickness in fifteen years. 



Moles and Earthworms. The mammals of the meadow 

 are the moles (Talpa europea), and evidences of their industry 

 are not far to seek. If one has time and a capacity for sitting 

 quite still one may watch the approach of the mole as it moves 

 the earth in its burrowing, one may see the " frightened" earth- 

 worms come to the surface, and the mole following them above 

 ground and moving about quite quickly half hidden in the thick 

 loose-set grass, and then the meal. It is interesting to think of 

 the time when the earthworms possessed the underground world 

 undisturbed by any moles, and could roam about till dawn without 

 fear of any early bird. It would be valuable to find some evidence 

 in Britain of the remarkable fact narrated by Professor Ritzema- 

 Bos that moles store earthworms for the winter, decapitating them 

 first so that while they remain fresh they cannot crawl away. A 

 tap on the mole's thin skull kills it, and there is much to see on 

 the dead body e.g. the soft velvety fur with vertically set hairs ; 

 the minute rudimentary eyes ; the extra sickle-bone at the wrist 

 that helps to make the hand so effective a spade ; the strong 

 shoulder girdle, keeled breastbone, and strong pectoral muscles ; 

 the forty-four teeth, and so on. It is not difficult to get the 

 pupils to discover the adaptive significance of some of these features. 



But the mole is not the only mammal of the meadow. The 

 common shrew (Sorex vulgaris), who also goes to the top of our 

 highest mountains, is at home in the meadow, and its " shrill 



1 See (Thomson) p. 222. 



