20 HEPORT UF r()MMISSlOXEK8 OF IXLAXJ) FISHERIES. 



can be protruded for a distance equal to the length of the star- 

 fish's arm. Having digested the food the stomach is withdrawn 

 to its normal position within the bod}-. 



Most of the animals upon which the star-fish prey are molluscs 

 protected bj^ hard shells; for example, the sea-snails, mussels, qua- 

 haugs, and oysters. How does the star get at the soft i^art of the 

 molluscs ? This question has given rise to a great deal of interest- 

 ing, not to say amusing, speculation, esx:)ecially with respect to the 

 oyster. 



An old tradition in England and this country is to the effect 

 that the star-fish takes the oyster bj^ sur^^rise and i)uts an arm 

 into its gaining shell ; then a fight ensues. Sometimes the oyster 

 is victorious while the star-fish retreats minus an arm, but often 

 the 03'Ster succumbs, since it cannot live long with its shell open, 

 and the star then devours its prey at leisure. There are two facts 

 that are sufficient to disprove this theory. In the first i^lace, the 

 oyster is veiy sensitive/ and feels the slightest disturbance in tlie 

 vicinity of the margin of the o^jen shell. In the second i)lace, the 

 shell does not open wide enough to admit the arm of the star. 

 Moreover, simi)le observation of the star-fish during the iDrocess 

 of eating disproves the story. 



It is suijposed by many that the star-fish secrets a poison into 

 the shell which causes the latter to open. But the valves of the 

 shell can be shut water tight and would exclude such a poison. 

 I have taken away from the star-fish oysters, muscles, and 

 drills which had already been opened, and placed them in an 

 aquarium where they soon recovered and behaved as though noth- 

 ing had happened. Schiemenz found the same to be true in the 

 case of the quahaug (Venus). 



Some have supposed that the star bores a hole through the shell 

 of the victim, but the star has no boring apparatus, and the shells 

 known to be opened by the star have no holes in them. 



It is a ver^^ common belief that an acid is secreted by the star 

 which dissolves the shell so that an entrance is effected. After a 

 successful opening, however, the litmus-paper shows no acid from 



