THE STAR-FISHES. 157 
had doubled its size, and the others had also increased. An 
orifice—that is, a mouth—began to form at the centre of this 
new group. The process of reproduction was then in full force, 
and in three days the four rays were completed; but when com- 
pared with the original arms, they were, of course, but Lilliputians. 
In a month’s time they had reached their proper size, and thus a 
new star-fish was produced from the amputated limb of another. 
The asterias are tormented with parasites. There is not per- 
haps an animal, terrestrial or marine, which does not serve 
as a home for another, or perhaps for many others. To live 
in dependence on another is a great physiological law. As a 
general rule, parasites belong to an inferior grade to that of the 
creature on which they exist; the contrary is very seldom the 
case. However, of this we have an instance in the parasite of the 
Culcita discoidea. Here is a little fish which passes its life in 
the intestinal cavity of a star-fish. This fish is called Oxybates 
Brandesit. The parasite is higher in the scale of life than the 
star-fish; for one is a vertebrate animal, and the other belongs 
to the inferior rank of the invertebrata.* 
Some of the star-fishes have a body—a little round disc—from 
which rays extend, which are supported by a series of vertebral 
formations. These are the Ophiurad@, so called from a fancied 
resemblance which the rays bear to the tail of a serpent. The 
arms are long, flexible, and wavy, and sometimes furnished upon 
their sides with spines and scales. In many species, which are 
termed Astrophytes, the arms bifurcate near their origin, and 
sometimes they are separated into two or three branches, which 
throw out again smaller rays, which are very fine and tortuous. 
In one individual no less than 81,920 of these have been counted. 
The elegant rays of the ophiurade move and twist themselves 
as they have occasion. They seize the prey which comes within 
their reach, and direct it to the mouth, which is always placed at 
the centre of the lower surface of the star-fish. The astrophytes 
appear to use their numerous arms as a net in which to catch 
their prey, and, at the same time, to hold it until it is wanted 
* Another little fish, the Merasfer Fontanesii, of Risso, lives as a parasite in the great 
intestine of the Holothuria royala. 
