ECHIN ODMRMAT A. 
289 
I never could understand why the dental framework of the sea- 
llf chin has been called Aristo tie’s Lantern, for this formidable apparatus 
resembles the front view 
a battery of cannon 
r^nre than a lantern. It 
insists of a series of 
Pieces designated by the 
Ila mes of compass, scythe, 
Pyramid, and plumula, 
^hich it would serve no 
Useful purpose to de- 
scribe. 
We have said that the 
^onth of the urchin is 
Monstrous in proportion 
*° its size, and the teeth 
of 
proportionate dimen- 
Fig. 117. Clypeabter rosaceus (Lamarck). 
Sions. As these project 
r ° tu a very formidable 
®r°nth, one can easily 
6 assured of the sharp- 
of their extremities 
J intruding his fingers on them. In fact, it is necessary that 
!^ ese organs should be singularly powerful, because, as we shall see 
'''■'tiler on, the sea-urchin makes incisions in the solid rock with 
etQ ! and hollows out shelter for himself. The strong and sharp 
^eth 
a 8 
tli, 
grow at the base in proportion as they are used at the points, 
ls the case with some of the rodent mammalia. By this means 
e y are always sharp and in good condition. Five groups of powerful 
la " s cl(’s are used to work these terrible grinders. 
this formidable mouth is attached an oesophagus or gullet, and 
intestine which extends along the interior walls of the carapace, 
Scribing the circumference of its principal contour, 
the regimen of the Echinidm is still imperfectly known ; neverthe- 
s > from the presence of shells, fragments of polypiers, crustaceans, 
• ev en other Echinodermata in their intestinal tube, it is to be 
Merred that a certain number of them at least are carnassiers or 
es 'n-eaters, while others are supposed on the same evidence to be 
u 
