500 THE AQUARIAN NATURALIST. 



vegetable feeders. They breed in spring, at which 

 season they often congregate in vast numbers, laying 

 their eggs among the Fuci imbedded in long and 

 slender gelatinous ribands. 



Beautiful as are the homesteads of many of the 

 shell-bearing Gasteropods, and harmless as their 

 occupants appear to the uninitiated, many of them, 

 as the aquariist will often find to his cost, are not 

 only eminently carnivorous and destructive, but are 

 provided with most formidable instruments where- 

 with to satisfy their appetites ; nay, strange to say, 

 it is amongst themselves they wage an internecine 

 war, as though they were resolved on mutual exter- 

 mination. And yet, perhaps, it would be difficult to 

 point out a race of animals apparently more secure 

 from attack than the inhabitants of such stone-built 

 citadels ; so impenetrable are their shells, and so com- 

 pletely closed by the stone door that guards the 

 entrance, we might think no robber' s cave we read of 

 in Arabian tales was ever more secure ; and yet, by 

 means as simple as they are admirable, the weakest 

 and apparently most despicable assailant succeeds in 



its attack, 



" and with a little pin 



Bores through their castle walls." 



We will select as an example of these carnivorous 

 tribes, the Purpura lapillus (PI. VIII. fig. 12), a species 

 to be met with abundantly on rocks or stones, in the 

 space between tide-marks, where it is the doubtless 

 unwelcome companion of periwinkles, limpets, and 

 top-shells, all of which, if they had a vote in the 

 matter, would probably prefer its absence ; for it is 



