1 -MOLLUSCA. 
bulk of the shell; yet let the creature be disturbed, 
and the whole is suddenly withdrawn into the ca- 
vity, so completely that not a trace of it is visible. 
* When shrunk within its shell,” observes Dr. 
Johnston, “ you might well deem any animal that 
could hide itself there, all too small and weak to 
carry about a burden larger and heavier than it- 
THE GIANT STROMBUS. 
self, and that safety might be here advantageously 
exchanged for relief from so much heaviness of 
armour, and from such an impediment to every 
journey. ‘There is in my small cabinet a fine spe- 
cimen of Cassis tuberosa, which measures fully ten 
inches in length, and upwards of eight in breadth, 
another of Strombus gigas is nearly one foot in 
