(J2 INTHODUCTION TO ZOOLOGY. 



forward the remaining parts of the body. E arth- worms move 

 but little abroad during the day-time, except when disturbed. 

 The young are produced from eggs, which, previous to their 

 being deposited by the mother, have undergone a certain degree 

 of development.* Their blood is red; but in some species it 

 is yellow, and in one it is a pale green, so that the mere 

 colour of the circulating fluid does not seem to be of tho 

 zoological importance attached to it by Aristotle. 



The mouth of our common Earth-worm (Lumbricus terres- 

 tris) has a short proboscis, but is destitute of teeth. Its food 

 consists of the decaying particles of animal and vegetable 

 matter, "the crumbs that fall from nature's bounteous table."! 

 By the ordinary process of chemical decomposition, these par- 

 ticles would be dissolved and lost. Swallowed by the Earth- 

 worm, they become converted into nutriment, are assimilated 

 to the substance of its body, and in this state minister to tho 

 support of beings of higher organization to that of birds 

 and fishes. 



On this subject, the Rev. Gilbert White, in his delightful 

 "Natural History of Selborne," has long since made the 

 following judicious observations: 



* ' The most insignificant insects and reptiles are of much 

 more consequence, and have much more influence in the eco- 

 nomy of nature, than the incurious are aware of; and aro 

 mighty in their effect, from their minuteness, which renders 

 them less an object of attention, and from their numbers and 

 fecundity. Earth-worms, though in appearance a small and 

 despicable link in the chain of nature, yet, if lost, would make 

 a lamentable chasm. For, to say nothing of half the birds, 

 and some quadrupeds, which are almost entirely supported by 

 them, worms seem to be the great promoters of vegetation, 

 which would proceed but lamely without them, by boring, 

 perforating, and loosening the soil, and rendering it pervious 

 to rains and fibres of plants, by drawing straws and stalks of 

 leaves and twigs into it, and, most of all, by throwing up 

 such infinite numbers of lumps of earth called worm-casts, 

 which being their excrement, is a fine manure for grain and 

 grass.'* 



The correctness of these views has recently received a 



* Owen, page 146. 



f Rymer Jones, page 328. 



