THE BEARDED ROCKLINGS. 213 



highly important we should do all we can to keep 

 it such. Its chief food is marine worms, small crus- 

 tacea, and small mollusca ; and the carapaces and 

 shells of the two latter may be found in its stomach 

 in every stage of decomposition and dissolution. The 

 cod becomes very tame in confinement, and is said 

 even to manifest signs of attachment to those who 

 feed it. The three-bearded rockling (Motella tricir- 

 rata), as well as the four and five-bearded rocklings, 



Fig. 141. 



Three-bearded Rockling (Motella tricirrata), 



are not distantly related to the cod and whitings. 

 They take their popular names from the barbels 

 which hang from the lower jaws, and which are pos- 

 sessed by the cod family generally. All of them are 

 nocturnal in their habits, and one of them, the five- 

 bearded rockling {Motella mustela) builds a nest for 

 her eggs in the crevices of the rockwork, made up 

 of corallines, sea-weeds, &c. The haddock (Gadus 

 cegelfinus) is another well-known species of cod, now 

 to be seen in some public aquaria. The coal-fish 

 (Merlangus carbonarius) is so named from the black 

 colour it frequently assumes. It is abundant in the 



