FOOD OF THE SEA-URCHINS. 223 



and it will even make a hearty meal of pure shell. 

 An Echinus of moderate size having seized a small 

 living crab, the victim seemed to be paralysed by 

 simple contact ; nor did it offer any resistance to its 

 ferocious foe. Another Echinus, not more than fif- 

 teen lines in diameter, fastened its extended suckers 

 on a small lobster, a Galathea ; but the latter, fortu- 

 nately for itself, directing one of its claws with suffi- 

 cient dexterity, cut the suckers asunder, and thus 

 freed itself from its assailant's deadly grasp. Indeed, 

 these animals seem to have a natural propensity to 

 destroy. Specimens not a quarter of an inch in dia- 

 meter will tear sea- weeds into fragments." 



Cavolini assures us that the Echini live upon sea- 

 weeds. Dr. Monro, on the contrary, tells us that 

 they live upon living shell-fish, which they seize and 

 secure by means of their suctorial ambulacral tubes. 

 " I therefore directed the fishermen to bring me 

 along with the Echini some living Buccina, to which, 

 as I supposed they would do, they attached them- 

 selves so effectually, that when I lifted the Echinus 

 out of the water, I found it could support with ease 

 a Buccinum which weighed nearly a quarter of a 

 pound " rather an odd proof of the nature of their 

 diet certainly ; for the same might be said of them 

 with respect to any stone of similar weight with 

 which they may happen to be brought in contact. 



" The Echinidans," says Mr. Kirby, " whose station 

 appears to be often near the shore upon submerged 

 ledges of rocks, feed upon whatever animal they can 

 seize. We have seen that they sometimes turn upon 

 their back and sides, as well as move horizontally. 



