390 



ANNELIDES. 



l to the anterior portion of the body. Nearly all of them inhabit tubes, and we terra 

 them Tubicolce. 



Others have upon the middle portion of their body, or all along their sides, branchiae 

 in form of arbuscules, crests, lamina?, or tubercles, in which vessels ramify. The 

 greater number live in mud, or swim freely in the water ; only a very few inhabiting 

 tubes. These we denominate Dcrsibranchiata. 



Finally, others have no apparent branchiae, and respire either over the surface of the 

 skin, or, as is believed in some cases, by their internal cavities. The greater number 

 live freely in water, or in mud ; some, however, in humid earth : and we designate 

 these Abranchiata. 



The genera of the two first orders have all silky bristles, of a metallic colour, upon 

 the sides, either simple or in bundles, and which supply the place of feet ; but in the 

 third order, there are some genera devoid of all such support* 



The particular study which M. Savignyhas made of these feet or locomotive organs, 

 has led him to distinguish, firstly, the foot or tubercle which bears the bristles, of 

 which there is either one only upon each ring, or two, one above the other, which he 

 respectively terms a simple or double oar ; secondly, the bristles which compose a 

 bundle upon each oar, varying much in consistence, and which either constitute true 

 spines, or fine and flexible filaments, that are often dentelated, barbed, or irregularly 

 so, &c. ; and thirdly, the cirrhi, or fleshy filaments, adhering either to the inside or 

 outside of the feet. 



With respect to their organs of sense, the two first orders of Annelides have gene- 

 rally tentacles to the head, or filaments, which, notwithstanding their fleshy consis- 

 tence, some moderns have designated antenna? ; and several genera of the second and 

 third orders have black and shining points, which have been regarded as eyes. The 

 organization of the mouth varies exceedingly. 



[The Annelides constitute one of the many small, but singular and highly interesting, 

 tribes of animals, which, from being upon the confines of the peculiar class or sub- 

 kingdom to which they in effect belong, exhibit, in a remarkable degree, the modifi- 

 cations of other higher groups : thus, by an ordinary observer, these creatures would 

 be at once classed as Worms ; and the common Earth-worm, one of them, would be 

 regarded as the type of the grand class of Linnaean Vermes, the great majority of which, 

 however, do not even belong to this great subkingdom, but to that of the Zoophytes, 

 from which these articulated animals are at once distinguished by the possession of red 

 Wood circulating in a well-defined system, and a far more perfect developement of the 

 nervous system ; still, in their vermiform appearance, and in the elongated filaments 

 with which many of them are furnished, they resemble certain Zoophytes, — on the 

 other hand, they approximate to the most imperfect Fishes, such as the Lampreys and 

 others, in which the spine has disappeared. Their annulose character, and nervous 

 system, however, bring them nearer to the true Annulosa, especially the Myriapoda ; 

 this will at once be evident by comparing the figures of Geophilus longicornis, given in 

 p. 486, with that of Syllis monilaris here figured. f Mr. Mac Leay accordingly con- 



* M. Savignyhas proposed a division of the Annelides according: to 

 their possessing locomotive silky bristles, or not so; reducing the 

 latter to the Leeches. M. de Blainville, who has adopted this idea, 

 ranges the bristled Annelides as a class, termed Entomoxnaires Che- 

 topodes, and the others as one designated Entomozoaires Apodes ; but 



he mingles with the Apodes many intestinal Worms, which M 

 Savigny does not admit. 



t Mr. Mac Leay considers that they form the immediate connexion 

 between such Vertebrata as Araphinxus and My.xine, and such Annu- 

 losa as Porocephalus, and other white-blooded Vermes, which have 

 the sexes distinct. (Ami. Nat. Hist., Feb. 1840.) 



