252 



THE BRITISH NATURALIST. 



[November 



largest animals come from the same Hand and bear equally the impress 

 of the Great Artificer. Our aquatic worm is only seven or eight lines 

 in length. It, however, seems to belong to a class of its own, at least 

 we know of no other class with which it can be included. . Terrestrial 

 animals live on land, aquatics in water, and amphibians sometimes on 

 land and sometimes in water. This one has the two extremities of its body 

 aquatic. Its head and tail are always in the water, and the rest of its 

 body is always out of the water. To understand this one must know 

 its shape. Like many insect s, it is composed of different rings. It has 

 eleven rings between the head and the tail. They are all almost 

 circular, or it resembles the beads of a chaplet threaded one after 

 another. This insect is almost always bent double in two parts like a 

 siphon. I must remark that one of these parts is longer than the other, 

 and that they are both almost parallel to each other, so that the head 

 and the tail are always near, the one to the other. The part that goes 

 from the bending to the tail is a little longer than that which goes from 

 the same bending to the head. It is, however, the sixth ring which is 

 generally in the middle of the elbow, or that part wh ere the animal is 

 bent. But the five rings that form the tail side are larger than the five 

 that form the head side. There are only the head and the tail, and the 

 ring nearest to the tail, that are constantly in the water ; the nine other 

 rings, or at least seven of the other rings, are out of it. This insect also 

 keeps close to the edge of still water, agitated water would not suit it ; 

 as soon as the water covers it a little more than we have said it is ill 

 at ease and withdraws itself. If, on the contrary, the water covers it 

 less, it instantly goes further into it. This worm being only about 

 eight lines in length, it would not be easy to make observations when 

 it is at the edge of a large piece of water, therefore it was in examining 

 it in glasses or cups, that I observed what I have just described. I 

 always saw it attach itself to the sides of the vessel in such a manner 

 that its bead and tail were in the water and the rest of its body out of 

 it. If, in inclining the vessel in one direction, I obliged the water 

 to cover it more, it instantly withdrew itself. If, in inclining 

 the vessel in a contrary direction, I obliged the water to leave 

 it, it hurried quickly in search of the water it had lost. For the 

 rest, its manner of walking or crawling caused me to examine it more 

 closely. It appeared to me to merit a place among the progressive 

 movements of the aquatic animals of which I have spoken in different 

 memoirs. In its natural manner of walking it is the middle of its body 

 which advances first towards the place to which the animal is approach- 

 ing, that is to say, the sixth ring is most in advance and seems to lead 

 the rest of the body, as the head does in fourfooted animals. In a word, 

 while this animal is in the act of advancing, it remains doubled up like 

 a siphon, and it is the sixth ring, in the middle of the body, that goes 



