314 
E CHINODERMS. 
breaking up their tissues; while others have an objectionable habit of shooting out 
a part of their intestines in long viscous strings; and it is owing to this that a 
common British form has gained 
the name cotton-spinner. It has 
been suggested that this habit has 
been acquired in connection with 
the presence in the intestine of 
small parasites, and these in their 
turn have their habits affected 
according as they live in holo- 
thurians that are or are not 
cotton - spinners. Among the 
parasites of holothurians should 
specially be mentioned a little 
fish of the genus Fiercisfer, that 
inhabits the intestine of some 
species, and has its food provided 
for it by the holothurian; this fish 
is described on p. 438 of Vol. V. 
Holothurians are of interest, as furnishing a food known 
as trepang, which ranks with edible birds’ nests among the 
delicacies of a Chinese table. The 
fishing for trepang, or beche-de-mer, 
as the holothurians are called by 
the Portuguese, takes place very 
largely in Oriental countries, and is 
being- extended to the Barrier Reef 
of Australia. All kinds are not 
equally esteemed, for some have too 
much calcareous deposit in their 
skin, and others get rid of their 
insides, and so become too lean. 
CLUB-LIKE SEA-CUCUMBER (RtlOJOCdo- 
dina) (nat, size). 
A DEEP-SEA HOLOTHURIAN, 
Psychrujpotes (J nat. size). DEVELOPMENT OF ECHINODERMS 
Few things about echinoderms are more remarkable 
than their modes of reproduction, which include both a 
sexual method, from the fertilised egg, and also one by 
budding or splitting of a single individual into two. 
Many echinoderms, as we have already seen, have the 
curious power of breaking off portions of themselves; as 
the brittle-star or crinoid can break oft' their arms. Also 
they are able to eject the whole or a part of their viscera, 
a faculty which has been specially developed in some of 
the holothurians. It is still more remarkable that the 
portions so broken off can be grown again, and that they 
A PLATED HOLOTHURIAN ( Psolus ). 
Some plates of the back, above 
the brood-pouch, are removed 
(enlarged 3 times). 
