68 GLAUCUS; OR, 
and of a warmer colour; those that I have seen are - 
even more spinous.” Such may have been the case 
in those I sent: but it has occurred to me now 
and then to dredge specimens of C. aculeatum, 
which had escaped that rolling on the sand fatal 
in old age to its delicate spines, and which equalled 
in colour, size, and perfectness the noble one figured 
in poor dear old Dr. Turton’s “ British Bivalves.” 
Besides, aculeatum is a far thinner and more 
delicate shell. And a third species, C. echinatum, 
with curves more graceful and continuous, is to be 
found now and then with the two former. In it, 
each point, instead of degenerating into a knot, as 
in tuberculatum, or developing from delicate flat 
briar-prickles into long straight thorns, as in acu- 
leatum, is close-set to its fellow, and curved at the 
point transversely to the shell, the whole being thus 
horrid with hundreds of strong tenterhooks, making 
his castle impregnable to the raveners of the deep. 
For we can hardly doubt that these prickles are 
meant as weapons of defence, without which so 
savoury a morsel as the molluse within (cooked and 
