268 
THE OCEAN WORLD. 
according to tlie professor, and envelopes the entire oyster in its W' 
most recesses, while, doubtless, distilling a poisonous liquid. T ' 10 
victim is thus forced to open its shell, and becomes the prey of tl |0 
enemy which envelopes it. 
Whatever may be the modes of procedure employed by the star- 
fish, it is now clearly ascertained, however incredible the fact may 
first appear, that it swallows oysters in the same manner as is prac- 
tised at the oyster shop. 
This little being, formed of five arms, and without any other appa- 
rent member, accomplishes a work which man is quite unable 
execute — it opens an oyster without an oyster-knife. 
If reasoning man had no other means of nourishment than oysters, 
and was without a knife to open them, it is very certain that with all 
his genius he would be puzzled how to get at the inaccessible aiiu 
savoury bivalve so obstinately closed against him. The star-fish d e " 
vours dead flesh of all kinds ; their sole occupation is to feed themselves 
and they keep up an incessant and active chase after all sorts of corrupt 
animal matter. The Asterias thus performs in the bosom of the set 
the same part that certain birds and insects play on shore ; they a 1 ' 0 
its scavengers, and feed their bodies upon the carcases of animal 
which, if abandoned to the action of the elements, would become a 
cause of infection. 
In the same manner that certain animals render the air healthy > 
the Asterias help, on a considerable scale, to keep the sea which shelter ' 8 
them in a pure and healthy state. Zoologists are not agreed upon 
the manner in which respiration operates on the star-fishes. Never- 
theless they think that the principal part in this phenomenon devolve 8 
upon the sub-cutaneous branchiae which in each ray constitute two 
double series of bladders. The function of circulation is equally 
unknown. The vascular apparatus is sufficiently developed in tfii & 
zoophyte, and appears to have for its centre an elongated canal will* 
muscular walls, which may with justice be honoured with the name o 
heart. A little ring surrounding the oesophagus, and from which 
issue certain delicate white chords, which aro prolonged into th 0 
furrows of the arms, present ns with all that can be designated a nervom 
system in the star-fishes. Among organs of sense we may mention , 88 
the apparatus of touch, the tentacular ambulacraira, as well as those 
which are disseminated upon the dorsal surface of the disk. The eyes a 10 
