260 THE OCEAN WORLD. 



according to the professor, and envelopes the entire oyster in its 

 inmost recesses, while, doubtless, distilling a poisonous liquid. The 

 victim is thus forced to open its shell, and becomes the prey of the 

 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 at 

 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 to 

 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 and 

 savoury bivalve so obstinately closed against him. The star-fish de- 

 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 perform in the bosom of the sea 

 the same part that certain birds and insects play on shore ; they are 

 its scavengers, and feed their bodies upon the carcases of animals 

 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 shelters 

 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 devolves 

 upon the subcutaneous 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 this 

 zoophyte, and appears to have for its centre an elongated canal with 

 muscular walls, which may with justice be honoured with the name of 

 heart. A little ring surrounding the oesophagus, and from which 

 issue certain delicate white chords, which are prolonged into the 

 furrows of the arms, presents us with all that can be designated a nervous 

 system in the star-fishes. Among organs of sense we may mention, as 

 the apparatus of touch, the tentacular ambulacra, as well as those 

 which are disseminated upon the dorsal surface of the disk. The eyes are 



