ISG 



ZOOLOGY 



Nereis lives on both plant and animal food. To capture its 

 pre}' it thrusts out a long proboscis, provided with two power- 

 ful jaws. The thrusting-out consists essentially 

 of a rolling in.side out, — just as the finger of a 

 glove may be rolled inside out. When the pro- 

 boscis is rolled in again, the jaws, retaining their 

 grip on the food, carry it into the food canal.' 

 While many kinds of small animals serve Nereis 

 as food, it is itself devoured by various fishes 

 which dig it out of the sand or capture it when 

 it swims free at night __ ^ 



Fig. 177- Lep- ^^ during the breed- 



idonotus, the " 



scaled worm, ing season. Such a 



Photo. i,y'w; favorite with fishes 



H- <^'- P- naturally makes ex- 



cellent bait, and is well known to 

 fishermen under the name " clam- 

 worm " or " sandworm." 



We have seen that Nereis lives ^ 

 for a short period each year a free 

 life, swimming in the sea. Accord- '' 

 ingly its l)ody is divided into rings 

 of nuiscle enabling it to writhe. 

 Locomotion by writhing is further 

 facilitated t)y the existence of a 

 pair of ap]iendages (parapodia) on 

 each segment. The appendages are 

 nearly alike on all the segments of 

 the Ijody. They diminish in size 



■ssJ^i 



however, toward the tail. Cor- Nat. size 



' See Fig. 160, 



' Fig. 178. — .'Vphrodite, a sea-mouse. 

 From Johnston. 



