290 



THE POPULAR SCIENCE MONTHLY. 



Mouth. 



Pharynx. 



Lii.mhricus is the name of the best-known genus, of which the species 

 have not been accurately distinguished and numbered ; but only a 

 part of them bring \x\i earth in the form of castings, and are engaged 

 in making tillable soil. They appear to be found wherever there 

 is moist earth containing vegetable matter, but seem to abound most 

 where the ground is loose and well charged with humus. Dryness 

 is unfavorable and even fatal to them ; but, although they are ter- 

 restrial animals, they have been found by M. Perrier to be capable of 

 living for a considerable time under water. During the summer, when 

 the ground is dry, and during the winter, when it is frozen, they 

 penetrate to a considerable depth in the earth and cease to work. 

 They are nocturnal in their habits, and may be often seen at night 



crawling over the ground, more often moving 

 their heads and bodies around while their tails 

 are still .inserted in their burrows. Only sickly 

 worms, such as are afflicted by the parasitic larva 

 of a fly, as a rule travel in the day-time ; and 

 those which are seen dead on the ground after 

 \- f heavy rains are supposed to have been creatures 



afflicted in some way that have died of weakness 

 rather than by drowning. They often lie quite 

 still close beneath the mouths of their burrows, 

 where their heads may be seen on looking for 

 them, and, in this position, offer a tempting bait 

 to birds. 



The body of a large worm consists of one or 

 two hundred almost cylindrical rings or seg- 

 ments, each furnished with minute bristles, and 

 is endowed with a well-developed mttscular sys- 

 tem. The mouth is provided with a little pro- 

 jection or lip, capable of taking hold of things, 

 and of sucking. Internally, a strong pharynx, 

 corresponding, according to Perrier, with the 

 protrusile trunk or proboscis of other annelids, 

 and which is pushed forward when the animal 

 eats, is situated behind the mouth. The pharynx 

 leads into the oesophagus, on each side of the 



Fig. 1. Diagram of ttie , , . . ., j. , 



Alimentary Canaz of lower part 01 which are three pairs of large 

 an Eaeth-Wobm (Lvm- 1 -1 i 1 < 



brieve), (copied from Ray glands, which secrete a surprising amount ot 



Lankester in " Quarterly -1 < < mi vi ^i 



Journal of Microscopical carbonate of lime. I hey are unlike anything 

 eeries, y p]. vi'i'!.' xv ' uw that is known in any other animal, and their use 

 is largely a matter of speculation. Mr. Darwin 

 thinks they are partly excretions of the excess of lime contained in 

 the leaves which the animal eats, and that they otherwise aid digestion 

 by affording a neutralizing agent against the acids of its food. In 

 mosl of the species the oesophagus is enlarged into a cup in front of 



(Esophagus. 



Calciferous glands. 



1 Esi jibagus. 



Crop. 



Gizzaid. 



Upper part of in- 

 testine 



