THE HOLOTHURIDA. 171 
out its length by five narrow ribbons of white silk, and its head 
surmounted by a living flower, whose twelve tentacles, of a dead 
white, fall behind in graceful curves. In the centre of these ribbon 
tissues, which rival in their delicacy any of the products of the 
silk-loom, is an intestine of the finest gauze, filled—completely 
filled—with grains of granite, their sharp points and rugged edges 
plainly discernible to the eye. Fancy such rough grains contained 
in a tissue finer than gauze! The walls of the body are barely one- 
sixteenth of an inch thick, and yet Quartrefages discovered seven 
distinct layers of tissue, skin, muscles, and membranes. The 
animal is protected by a kind of mosaic work formed of minute 
SPICULZ OF THE TENTACLES OF THE SYNAPTA. 
calcareous shields, each furnished with double hooks, the points of 
which are barbed like the arrows of the Caribbeans. 
When kept in a vase of sea water, and unable to get any food, 
the synapta detaches portions of its own body. Below the part 
which is to be cast off a ring is formed, which gradually contracts, 
and thus the part suddenly drops off. It would appear that the 
animal, feeling it had not sufficient food to support its own body, 
was able to abridge its dimensions, by casting off the parts most 
easily spared, just as we should dismiss the useless mouths from 
a besieged city. This is a most singular mode of combating the 
approach of famine, and the synapta pursues the strange device to 
the very last moment; and, finally, nothing is left save a round 
ball, which is the head covered with tentacles. Thus, to preserve 
life in its head, it has voluntarily parted with all its other members. 
What marvels of animal life does the world of the sea contain! 
