160 JUNE. 



The most common members of the class Annelida, 

 that we meet with in these situations, are different 

 species of the genus Nereis, which are for the most 

 part worms of considerable size, usually brown or 

 green, with a changeable metallic lustre above, and 

 brilliantly pearly beneath. They have a distinct head, 

 of a squarish form, terminating in two swollen fleshy 

 knob -like antennae, and furnished with four pairs of 

 thread-like tentacular cirri, which project on each side 

 like a cat's whiskers. The body is plump, though some- 

 what flattened, and bears on each side a row of fleshy foot- 

 warts, which are pierced for the extrusion of the curious 

 bristles that are so characteristic of these marine worms. 



We can scarcely turn one of these flat stones which 

 lie half-buried in sandy mud at the water's edge without 

 finding one or more of this tribe. Let us try. Here 

 at once is a specimen, one of the finest as well as one of 

 the commonest of all. 1 The upper surface is of a warm 

 fawn-brown ; but the beautiful flashes of iridescent 

 blue that play on it in the changing light, and the 

 exquisite pearly opalescence of the delicate pink beneath, 

 are so conspicuous as to have secured it the title of 

 " Pearly," par Eminence. As you gaze upon it you see 

 the great dorsal blood-vessel or heart, as a dark red 



1 Nereis margaritacea, of which the head and fore parts of the body 

 crawling over a stone are depicted at the left-hand corner of Plate xvin. 



