Earth- Worms in History. 5 1 



with leaves, apparently to prevent their bodies from coming 

 into contact with the cold, damp earth, and by the still other 

 fact that they completely close their burrows during the 

 winter. 



Some remarks about the structure of the earth-worm now 

 appear apropos. Its body consists of from one hundred to 

 two hundred almost cylindrical rings, each provided with 

 minute bristles. The muscular system is well developed, 

 thus enabling these animals to crawl backwards as well as 

 forwards, and to retreat by the help of their affixed tails into 

 their burrows with extraordinary rapidity. Situated at the 

 anterior end of the body is the mouth. It is furnished with 

 a little projection, variously called the lobe or lip, which is 

 used for prehension. Behind the mouth, internally located, 

 is a strong pharynx, which is pushed forwards when the 

 animal eats, corresponding, it is said, with the protrudable 

 trunk of other Annelids. The pharynx conducts to the 

 oesophagus, on each side of the lower part of which are 

 placed three pairs of large glands, called calciferous glands, 

 whose function is the secretion of carbonate of lime. These 

 glands are very remarkable organs, and their like is not to 

 be found in any other animal. Their use is connected in 

 some way with the process of digestion. The oesophagus, 

 in most of the species, is enlarged into a crop in front of the 

 gizzard. This latter organ is lined with a smooth, thick 

 chitinous membrane, and is surrounded by weak, longitudi- 

 nal, but powerful transverse muscles, whose energetic action 

 is most effectual in the trituration of the food, for these worms 

 possess no jaws, or teeth of any kind. Grains of sand and 

 small stones, from the one-twentieth to the one-tenth of an 

 inch in size, are found in their gizzards and intestines, and 

 these little stones, independently of those swallowed while 

 excavating their burrows, most probably serve, like mill- 

 stones, to triturate their food. The gizzard opens into the 

 intestine a most remarkable structure, an intestine within 

 an intestine which runs in a straight line to the vent at the 



