296 THE OCEAN WORLD, 
of sixty vessels, having a hundred men on board, had left Madagascar 
two months previously in the same pursuit. 
Among the Holothuria, one particular genus, Synapta, is distin- 
guished from others of the family by the absence of the ambulacral 
feet, and by the fact of its uniting both sexes in one individual. 
Synapta Duvernea is represented in Prate X. M. Quatrefages, who 
discovered it in the Channel, gives the following description of it in 
his work, “Les Souvenirs d’un Naturaliste.” “Imagine,” he says, “a 
cylinder of rose-coloured crystal, as much as eighteen inches long and 
more than an inch in diameter, traversed in all its length by five 
narrow ribbons of white silk, and its head surmounted by a living 
flower, whose twelve tentacles of purest white fall behind in a graceful 
curve. In the centre of these tissues, which rival in their delicacy 
the most refined products of the loom, imagine an intestine of the 
thinnest gauze gorged from one end to the other with coarse grains of 
granite, the rugged points and sharp edges of which are perfectly 
perceptible to the naked eye. 
“ But what most struck me at first in this animal was, that it seemed 
literally to have no other nourishment than the coarse sand by which 
it was surrounded. And then, when, armed with scalpel and micro- 
scope, I ascertained something of its organisation, what unheard-of 
marvels were revealed! In this body, the walls of which scarcely 
reach the sixteenth part of an inch in thickness, I could distinguish 
seven distinct layers of tissue, with a skin, muscles, and membranes. 
Upon the petaloid tentacles I could trace terminal suckers, which 
enabled the Synapta to crawl up the side of a most highly polished 
vase. In short, this creature, denuded to all appearance of every 
means of attack or defence, showed itself to be protected by a species 
of mosaic, formed of small calcareous shield-like defences, bristling 
with double hooks, the points of which, dentated like the arrows of 
the Caribbeans, had taken hold of my hands.” 
' If one of these Synapta is preserved alive in sea-water for a short 
time, and subjected to a forced fast, a very strange phenomenon will 
be observed. The animal, being unable to feed itself, successively 
detaches various parts of its own body, which it amputates spon- 
taneously. A great compression or ring is first formed, and then the 
separation of the condemned part takes place quite suddenly. “It 
would appear,” says M. Quatrefages, ‘that the animal, feeling that it 
had not sufficient food to support its whole body, was able successively 
to abridge its dimensions, by suppressing the parts which it would be 
most difficult to support, just as we should dismiss the most useless 
mouths from a besieged city.” 
