ANNELLID^. 



119 



and some of the other Eastern countries, when the 

 earth is moist, by fastening upon the legs in multi- 

 tudes, and which are as difficult to be removed as mos- 

 quitoes, can draw their bodies out to as fine a staple 

 as the hair of the human head, or even finer, and thus 

 it is scarcely possible to exclude them from any place. 

 When drawn to their utmost possible thinness, they 

 retain their strength, and thus they glide away with 

 wonderful velocity, so that one can scarcely discern 

 the expansion and contraction of the rings. Those 

 that have this power have no bristles, or other sub- 

 stitutes for feet, upon the rings ; so that they are 

 enabled to bring the whole of these into action in 

 each progressive effort. Their means of holding on 

 are two suckers, one placed at each extremity ; the 

 posterior one being fixed when the body attenuates 

 and lengthens, in advance, and the anterior one when 

 the body thickens and is drawn towards the head. 

 Thus these animals proceed by a sort of steps, each 

 as long as the distance to which the body stretches 

 when attenuated ; and performed by the two suckers 

 something in the same manner as if these were two 

 feet ; only the rear foot never comes quite so far in 

 advance as the front one. Those with bristles to the 

 rings do not move so rapidly along, but crawl and 

 wriggle, moving parts of the body in succession, and 

 not using the whole of it for single majestic strides. 



The Annellida? are, by Cuvier, designated " red- 

 blooded worms ;" because their blood is generally of 

 that colour ; and, which is not a little singular, the 

 flesh, if flesh it can be called, of some of the land 

 ones, has, both in its recent and its putrid state, nearly 

 the same smell as that of the mammalia. Their bodies 

 are more or less elongated, and more or less capable 

 of elongation when they walk ; they are always di- 

 vided into numerous small rings, of which the first is 

 usually styled the head, and contains the mouth, and 

 probably the organs of sense, but the latter are ob- 

 scure in all the species, and in some they cannot be 

 traced. The mouth, in some instances, consists of 

 jaws more or less developed and strong, and some- 

 times of a simple tube. There are no visible nostrils 

 or ears ; and the dark spots, which in some are 

 regarded as eyes, are very questionable, and they 

 are wanting in very many of the species. 



The circulating system is double, consisting of both 

 arteries and veins, sometimes without anything that 

 can be considered as a heart, and sometimes with 

 several distinct fleshy ventricles. The organs of 

 respiration differ much both in position and in struc- 

 ture. Sometimes they are situated in the posterior 

 part of the body, sometimes externally on the sides, 

 and sometimes in the interior of the body. Those 

 which inhabit the land, or the earth rather (for they 

 live under the surface rather than on it), have the 

 breathing apparatus always internal ; and it must be 

 considered as lungs. Those which inhabit the 

 water (and the majority of them live more in the 

 mud and silt than in pure water), have the breath- 

 ing apparatus sometimes internal, when the body 

 is naked, and always external when they live in 

 tubes. The tubes which they inhabit differ however 

 from the shells of the mollusca, even when these are 

 tubular in their form. The annellidaa secrete part of 

 the tube in all cases, that is, the cementing matter 

 by which the harder substances are held together ; 

 and when the harder matter is salts of lime, they 

 probably secrete these also. But the tube forms 

 no part of the animal, and is not in any way at- 



tached to it ; it is merely a house or case which it 

 inhabits, in so far defended from danger, and which 

 it has the power of enlarging as necessity requires. 

 In all those species which inhabit the water (and 

 they are far more numerous than the land ones), the 

 breathing apparatus is to be considered as gills ; and 

 those gills are often of very elegant structure. 



The nervous system consists of a double longitu- 

 dinal chord, united in two or more ganglions ; but 

 it is difficult to trace the minute ramifications of the 

 nervous tissue, and still more, perhaps, to determine 

 the number of senses or the organs in which the 

 specific ones are allocated. It is certain, however, 

 that many of these animals have extreme sensibility 

 in some way or other ; but whether that belongs to the 

 whole surface of the body, or to any particular portions 

 of that surface, has not been, and in all probability 

 cannot be ascertained. The use of the common leech, 

 in foretelling changes of the weather, long before these 

 are cognisable by any of the human senses, or even 

 by the generality of hygrometrical instruments, is well 

 known ; and the common earth-worm is also exceed- 

 ingly sensitive ; but whether its sensibility arises from 

 the mere concussion of the earth, or the air acting 

 upon its muscular and sentient system generally, or 

 whether it is to be considered as a peculiar modifi- 

 cation of the sense of hearing, has not been ascer- 

 tained. In the reproductive system, the greater 

 number, if not all the class, are true hermaphrodites, 

 but not, in as far as is known at least, self-fertilising 

 in any of the species. In many of them, however, 

 the pairing is reciprocal, the young are brought forth 

 alive, and undergo no metamorphosis. 



Though the place which the annellida; occupy in 

 nature appears to be a humble one, they are by no 

 means without their usefulness. The marine species, 

 which are by far the most numerous, supply a large 

 portion of the food of many of the shore and bank 

 fishes ; and they furnish the fisherman with one of 

 his most easily-acquired and useful baits. Of the 

 land species, the use on land is not so clearly seen, 

 because they generally disfigure lawns and other 

 portions of grass which mankind wish to keep neatly 

 trimmed ; and as their chief enemy under ground is 

 the mole, he, in his hunting after them, disfigures the 

 surface much more than they do. Still about the 

 time when larks and various other species of ground 

 birds begin to flock, the common earth-worms are 

 much on the surface, and afford the birds an abundant 

 supply of food, while the young of the worms come 

 in time to supply largely the young of many birds. 

 It is probably in the waters, however, that even the 

 land species are of the greatest utility. When the 

 meadows are flooded during the rains the worms are 

 driven from their holes under ground, and carried 

 down in vast numbers by the current of the water ; 

 and whenever that water stagnates, and especially 

 where it forms eddies, they are deposited, and the 

 fishes, trout especially, are on the qui vive, feast 

 daintily, and become rich prizes for the angler. Nor 

 is it to these alone that the annellidse are highly 

 useful. Many of the flat-billed birds, whether they 

 dabble in the shallows, or dive where the water is a 

 little deeper, 'subsist in great part upon the annel- 

 lidte ; and the flesh of those that do so is far superior 

 to that of the species which live chiefly upon fish. 

 The annellida?, in many of their characters, have a 

 considerable resemblance to the mollusca ; and it is 

 worthy of remark, that birds or fishes, which feed 



