62 
ZOOLOGY. 
Our commonest sea-worm, sometimes called the ^^clam- 
worm^^ is Nereis virens (Pig. 68). It lives between tide- 
marks in holes in the mud, and can be readily obtained. 
The body, after the head, eyes, tentacles, and bristle-bear- 
FiG. 67 — Clymenella torquata, natural size. 
ing feet have been carefully studied, can be opened along 
the back by a pair of fine scissors and the dorsal and ven- 
tral red blood-vessels with their connecting branches ob- 
served, as well as the alimentary canal and the nervous 
system. 
This worm is very voracious, thrusting out its pharynx 
d i 
h ^ 
Fig. 68 —Transverse section througrh the body of a Nereis, d, dorsal vessel or 
heart; c'. circular blood-vessel; h, ventral vessel; n, nervous cord or granglia; 
/, artery to swimming foot s''; i, intestine; s, setae or bristles. After Turn- 
bull, from Emerton. 
and seizing its proy with its two large pharyngeal teeth. 
It secretes a viscid fluid lining its hole, up which it moves, 
pushing itself along by its bristles. At night it le^ve^ 
its hole^ swimming op the surface of the water. 
