THE CAKE-URCHIN. 



547 



tingly place a foot upon them. Mr. F. D. Bennett, in his account of a "Whaling Voyage," 

 had practical experience of these sharp spines : "On one occasion, when searching for fish in 

 the crevice of a coral rock, I felt a severe pain in my hand, and, upon withdrawing it, found 

 my fingers covered with slender spines, evidently those of an Echinus, and of a gray color, 



HEART-URCHIN. Ptrinopsis lyrifera. (Natural size.) 



elegantly banded with black. They projected from my fingers like well-planted arrows from 

 a target, and their points, being barbed, could not be removed, but remained for some weeks 

 imbedded as black specks in the skin. 



" Its concealed situation did not permit me to examine this particular Echinus, but I 

 subsequently noticed others of a similar nature fixed to the hollows jn the rocks ; they were 

 equal in size to the Echinus ci-daris, and their body was similarly depressed, but the spines 

 were long, slender, and more vertically arranged, and their points finely serrated. Their color 

 was jet-black. These animals adhered so firmly to the rocks, that they could not be detached 

 without difficulty. 



"When closely approached, they gave an irritable shrug to their spines, similar to that 

 displayed by the porcupine or hedgehog. It was difficult to say if the hand had been brought 

 in perfect contact with this Echinus before it was wounded by its weapons. In some experi- 

 ments, I approached the spines with so much caution, that had they been the finest pointed 

 needles in a fixed state, no injury could have been received from them ; yet their points were 

 always struck into my hand, rapidly and severely. The natives are well aware of the offensive 

 character of these animals, and caution the stranger against handling them." 



The same author mentions that a species of Cidaris is largely eaten by the South Sea 

 Islanders, and that in various places on the sea-shore there are large heaps of its shells and 

 spines, showing that feasts have been lately held in that locality. 



THE curiously-formed Echinus which is shown in the illustration on next page is popularly 

 called the CAKE-URCHIN, on account of its remarkably flattened form. It belongs to a family 

 which are generally called Shield-urchins, from their flat, disc-like shapes. The shell is wonder- 

 fully flattened and slopes rapidly from the centre to the circumference. The general shape and 



