212 Natural History of the Earth-Worm^ 



Art. VI, The Earth-Wonn, considered ivith reference to Horticulture. 



By G. J. 



The common earth-worm (T^umbricus terrestris Liti.) has a 

 long cylindrical contractile body, composed, when lull grown, of 

 from 100 to 150 narrow segments or rings, of a dusky red or 

 flesh-colour. It has neither eyes nor tentacula, nor, indeed, 

 any external appendages, and the head is only to be distinguished 

 from the posterior extremity by being narrower and more pointed. 

 About one third of its length from the snout we perceive a sort 

 of belt (clitellum) on the body, embracing from six to nine rings, 

 which are more prominent and fleshy than the others. This 

 belt begins at the thirty-second segment, and indicates the po- 

 sition of the organs required for the reproduction of the species; 

 and, as the worm is hermaphrodite, it follows that every indi- 

 vidual should have this belt similarly formed, but age and the 

 influence of the generative action cause it to vary considerably 

 in its degree of distinctness, for it swells out in the season of 

 love and becomes less marked, or even undistinguishable, when 

 this has passed awa}'. Every ring of the body is furnished with 

 eight short spines or bristles, placed in pairs, so that taken 

 together they foi-m four double rows along the sides. These 

 spines are scarcely visible without the aid of a magnifier, and 

 are subservient to locomotion. On the ventral surface of the 

 sixteenth or seventeenth ring there is a pair of pores or fissures 

 raised on small mammiform processes ; and there is a similar 

 pair, but so minute as to have been generally overlooked, on the 

 twenty-seventh or twenty-eighth. The former pair are inti- 

 mately connected with the reproduction of the species, but the 

 function of the latter is uncertain. Besides these pores there is 

 a series of very minute ones along the back, one pore to each 

 ring, except to the anterior ones, which are unprovided with 

 it. They are most easily seen near the middle of the body, and 

 especially on that part of it which intervenes between the six- 

 teenth mammiferous ring and the belt. The series consists 

 altogether of from 110 to 120 pores, and they are believed to be 

 the entrances to the oblong pulmonary vesicles arranged in a 

 series along the sides, and in which the blood of the worm is 

 aerated. Some good naturalists afiirm, however, that they are 

 merely mucous cysts for furnishing the slimy fluid which lubri- 

 cates the surface ; and Morren, while he maintains their tracheal 

 character and use, is also inclined to admit that they may be at 

 the same time ducts for the issue of the excretion just mentioned. 

 The earth-worm has a well developed ganglionated nervous 

 system, but from the non-existence of the proper organs, phy- 

 siologists have come to perhaps a hasty conclusion that its senses 

 must be limited to those of taste and touch. The latter every 

 thing proves to be exquisite, and is the great regulater of the 



