86 SUPPLEMENT ^ 



seems probable that it can proceed to form another. Pallas, 

 in fact, informs us, that when it is very much annoyed there, 

 it will- issue forth spontaneously, and make its escape by 

 a vermicular kind of movement. 



The Amphitrite is a genus of marine worms, whose 

 character consists in having the head furnished with two 

 pieces of a metallic lustre, and similar in form to combs. 

 These animals, for the most part, inhabit tubes, which they 

 form by agglutinating small grains of sand or fragments of 

 shells, and which are sometimes fixed, and sometimes free, 

 according to the species. The body of the amphitrite is in 

 the form of an elongated cone, and is ordinarily terminated by 

 a long and tubular tail. The rings which compose the body 

 support all, or in part, on each side, a fasciculus of some stiff 

 setae, which the animal employs for motion. There are also 

 at each of these rings some fleshy filaments. The gills of the 

 amphitrite are attached to the anterior part of the body only, 

 as happens with all the worms that inhabit tubes, because 

 gills attached to the other parts of the body, which are sunk 

 in the tube, would be useless for respiration ; these gills are 

 in the form of a plume of feathers, and their greatest number 

 is four pair. The head of the amphitrite is as it were ti'un- 

 cated : around its mouth are filaments, more or less numerous, 

 which serve as tentacula ; the two brilliant combs are placed 

 underneath. It is probable that the animal makes use of 

 them to attract towards it the bodies which are to become its 

 prey, or the grains of sand which it desires to attach to its 

 tube. 



The amphitrites have, for the most part, a skin so fine, and 

 so transparent, that all their interior is perceptible through it ; 

 this interior generally consists only in an intestinal canal, as 

 thin as the skin itself, and almost always filled with sand. 

 There are, however, some species which have a muscular 



