110 RAMBLES OF A NATURALIST. 



exposed to view within three of their segments ; next 

 come the Echiuridae, whose zoological affinities with 

 this class are merely shown by the external indica- 

 tions afforded by the presence of several exsertile 

 and retractile hooks ; here too we have the Sipuncu- 

 lidas, whose cylindrical bodies exhibit neither mem- 

 bers nor the slightest trace of division into rings * ; 

 the Dujardiniae, which possess no apparent res- 

 piratory organs, and whose feet, furnished with long 

 silken threads, do not serve the purpose of locomo- 

 tion, animals which move through the water by 

 means of little tufts of vibratile cilia, arranged on 

 each side of the body like the paddles of a steam- 

 boat. To the tubicolous Annelids belong the Chlo- 

 rema3, which have green blood, circulating through a 

 body surrounded by velvety hairs, embedded in a 

 sort of transparent jelly, and which can conceal their 

 heads and branchiae in a kind of box, formed of in- 

 tertwined silken threads. Here, too, we find the 

 Amphicorae, animals which are provided with eyes at 

 the extremity of their tails as well as in their heads ; 

 the Terebellas, which, realising the fable of Briareus, 

 extend their hundreds of arms to a distance of nearly 

 a yard in search of the grains of sand and broken 

 shells, with which their temporary abodes are con- 

 structed ; and, lastly, there are the Sabellae, whose 

 fan-like branchiae often measure upwards of a foot in 

 diameter when fully expanded ; besides these there 

 are hundreds of other equally curious species, of 



* The Echiurus and the Sipunculus were placed by Cuvier 

 amongst the Radiata, by the side of the Holothurise. 



