190 POPULAR HISTORY OF THE AQUARIUM. 



Nereis bilineata. 



The Two-lined Worm is of a light red colour^ with two 

 white Hues running all down the body. It has been observed 

 to inhabit the deserted shells of Buccimim, in connection with 

 the Hermit, or Soldier Crah, Pagurus Bernhardus. While 

 feeding the latter, Mr. Gosse observed the worm to pro- 

 trude from between the body of the Crab and the Whelk, 

 glide round the Crab's cheek, pass between the upper and 

 lower foot-jaws, seize and carry off the morsel of food, re- 

 treating with it into his hole to consume it at leisure. Some- 

 times the Crab would put his claws into the hole and recover 

 the prize ; sometimes he would startle the Worm and make 

 him let it go ; at other times he would submit to his loss 

 and disappointment like a philosopher : a curious associa- 

 tion this, between the ''soldier" and the "thief." 



Aphrodita aculeata. 



The common ''Sea-Mouse" attracts attention by the 

 shining metallic lustre of its coat of bristles. Although a 

 worm in nature, its shape is oval, and its figure plump. 

 It is frequently met with in dredging over muddy ground, 

 and is sometimes thrown up on the beach. It is three 



