LECTURE X. 
153 
high degree of contractile power, and are furnish- 
ed at the extremity with a slightly expanded tip, 
which acts as a sucker or fastener. By these feel- 
ers also the Echinus takes its prey, fastening ea- 
sily on any small shell-fish in its way, and securing 
it, by applying to the shell the tips of its feelers 
and dragging it to its mouth. This species is 
considered as no unpleasant article of food, and 
was a dish well known to the ancient Romans. 
The internal structure of the spines, if closely ex- 
amined, will be found to bear a considerable re- 
semblance to those of the hedge-hog, the general 
structure being the same in both, though the one 
is of a horny, and the other of a calcareous sub- 
stance. To particularize the Exotic Echini would 
be an endless task. Among the most remarkable 
species is the flattish-bodied Indian Echinus, with 
extremely large, thick, club-shaped spines, of a 
violet colour, barred with white. This curious 
species, with several of its most remarkable va- 
rieties, occurs in the highest perfection in the Le- 
verian Museum. The shells of the Echini in ge- 
neral, when dried, and divested of their spines, 
generally present a very elegant and beautiful 
appearance, the pattern of the jointed subdivisions 
