71 



happen to lie near their burrows. They have three distinct methods of conveying objects 

 to their holes. That usually resorted to, at any rate by those in confinement, is to 

 suck into their mouths a portion of the object and then draw back by contracting the 

 muscles of the body ; another mode is to take hold of the edge of such objects as leaves 

 or pieces of paper by folding the upper lip over the edge and holding it between the two 

 lips ; the other way is perhaps the most remarkable, and consists of pressing the mouth 

 tightly against smooth objects, such as small stones embedded in a gravel walk, or even of 

 a flat leaf occasionally ; then by drawing back the pharynx a vacuum is created and the 

 object is withdrawn with great force, on exactly the same principle as the toy made by 

 schoolboys of a small piece of wet leather with a piece of string through the centre, and 

 which, when trodden down evenly and tightly around the edges on a flat even stone will 

 raise a very great weight. Occasionally, too, no doubt small pieces of leaves and other 

 small objects are drawn back to their holes by sticking to the mucous covering of their 

 bodies. After the first segment the body rapidly increases in size until it reaches the 

 average dimension ; but in a full grown worm, particularly at the season of reproduc- 

 tion, when it becomes a highly important organ " a part of the body, into which more or 

 fewer of the segments, (according to the species) between the twenty-fourth and thirty- 

 sixth inclusively, enter, is swollen, of a different colour from the rest, provided with 

 abundant cutaneous glands, and receives the name of the Cingulum or Clitellum.'' This 

 singular organ has sometimes given rise to the erroneous opinion that if worms were 

 accidentally cut in two the two parts would come together again and join, or that the two 

 portions would live, the head end forming a tail, and the tail end growing a new head. 

 The absurdity of these views is however apparent when it is remembered that the 

 nervous system consists of two cerebral ganglia or nerve centres, both of which are 

 placed in the anterior end of the animal, they are lodged in the third segment, and are 

 connected with the double chained nervous cord which extends through the whole length 

 of the body beneath the intestine. The circulatory system consists essentially of a 

 dorsal trunk situated, over the intestine, which carries the blood from behind forward, and 

 a ventral or sub-intestinal one conveying the fluid in the opposite direction. The blood is 

 red but has no corpuscles, and is quite different from that of vertebrates. The circulation 

 may be easily observed. If a small worm is taken out of the ground for a short time 

 and kept in water, it will void the earthy contents of its body, and will become sufficiently 

 transparent to show the circulation, if slightly compressed between two slips of glass and 

 examined with an ordinary magnifying glass. 



The Oligochseta are hermaphrodite, the two sexes being united in the same indi- 

 vidual, but two individuals pair together, the sexual elements are developed in certain 

 anterior segments. 



Earthworms do not possess any special respiratory organs, but breathe principally 

 by the skin and partly by the vascular system on the walls of the intestine. 



In vol. III. of Field and Forest (1877) there is an elaborate description of the 

 muscular system of Lumbricus, written by Dr. A. C. Stokes. This article is of great 

 value, as it is a record of extensive and careful original observations. At page 1 38 we 

 find : " Down the back of the creature in the middle line, one in each intersegmental 

 ring, is a row of circular openings. On the inner surface of each segment, therefore, 

 below the longitudinal muscle, is a muscle parallel with the length of the worm, and 

 extending from the lower edge of the orifice above to the upper edge of the aperture 

 below. The two ends are thickened vertically and slightly broadened, whence they 

 gradually narrow toward the centre. What the use of these openings may be it is impos- 

 sible to conjecture. They seem to have no connection with any of the internal organs, 

 but to form a direct communication between the external air and the general cavity. 

 The function of the muscles is evident. By their contraction they must widen the orifices, 

 naturally found closed and invisible until pulled open by needles on the stage of the 

 microscope, in imitation of the muscular action." 



I must confess that I have been unable to detect these orifices ; but as they are men- 

 tioned by other observers, this must have been owing either to want of skill on my part 

 or to imperfections in my instrument. Is it not possible that these orifices may act as 

 reservoirs for air, and that it is owing to their presence that earthworms can exist for 



