ECHINODERMATA. 
267 
fold of its internal membrane; the first chamber, thus limited, appeals 
be more especially devoted to the transformation of the elementary 
Matter into a liquid paste, which passes, in small portions, into the 
u Pper chamber. This is continued upwards through a small intestine, 
Ul| d communicates laterally with five cylindrical prolongations, which 
e ach divide themselves again into two much elongated tubes, furnished 
' v hh a double series of hollow branches, each terminating in a cul- 
de-sac.” These organs advance into the interior of the rays or arms 
the Asterias. 
Imagine, then, an animal bearing digestive tubes in its arms the 
a »rne organ serving for digestion and progression. What lessons in 
e °onomy does not the study of Nature teach us ! The products of 
digestion find an absorbent surface of great extent in the rays of the 
•^sterias. They ought necessarily* to pass rapidly from it into the 
Clr cumjacent nourishing fluid. 
I he star- fishes are very voracious ; they even attack mollusks which 
are covered with shells. M. Pouchet mentions having taken eighteen 
^Pecies of Venus intact, each being six lines in length, (loin the 
8 fomach of one large Asterias which he dissected upon the shores of 
Mediterranean. " It is now even said that the star-fishes eat many 
°ysters. 
Ancient naturalists were not ignorant that the star-fish was capable 
of eating oysters ; but they believed that they waited for the moment 
^Aen the bivalve would open its valves to introduce one of their rays 
foto the opening. They imagined that having thus put one loot into 
other’s domicile, they soon put four, and finished by reaching and 
pouring the savoury inhabitant of the shell. Modem observations 
hav e modified the ideas of former naturalists upon this point. In 
° r der to obtain possession of and swallow an oyster, it appears that 
tlle star-fish begins its approaches by bringing its mouth to the closed 
'Ages of the oyster-shell ; this done, with the assistance of a particular 
’fluid which its mouth secretes, it injects a few drops of an acrid or 
v «ftomous liquid into the interior of the oyster-shell, which forces it 
fo °pen its valves. An entrance once obtained, it is not long before 
lt; is invaded and ravaged. Professor Eymer Jones gives another 
ex planation of the transaction. According to this naturalist the 
°yster is seized between the rays of his ravisher, and held under Ins 
’Uoiith by the aid of his suckers ; the Asteria then inverts its stomach, 
