342 FUNCTIONS AND INSTINCTS. 



of under-tillage to pasture and other lands, and 

 by the casts which they every where throw up, 1 

 they help to manure the soil, and do the same 

 for pastures, that the spade does for the garden 

 and the plough for arable land, place the soil 

 that laid below above. Their food being vege- 

 table detritus, what passes from them must be 

 very good manure. 



The anatomy of these well-known animals 

 is very singular and well worthy the attention 

 of the physiologist and zootomist, the only 

 circumstance relating to it that I shall here 

 mention is that their long body is not only 

 divided externally into rings, but internally into 

 an equal number of cells separated from each 

 other, if I may so speak, by a kind of dis- 

 sepiment or diaphragm there are more than 

 a hundred of these cells in the common species, 

 as appears by Mr. Bauer's admirable figures, 2 

 to which I must refer the reader for further infor- 

 mation on this subject, first observing that there 

 seems some analogy between the cells of the 

 earth-worm and the joint of the tape-worm. 



The motion of these animals, and of many 

 other Annelidans, is accomplished by means of 

 the rings of their body and their lateral bristles ; 

 the latter the Creator has given to them, in the 

 place of legs : pushing with the anterior portion 

 of these against the plane of position, by con- 



* See Appendix, Note, 26. pfoi Trans. 1823. 



