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THE POPULAR SCIENCE MONTHLY 



of sponges. This little lobster-like animal has one very large claw and 

 one small one, and when captured it snaps the nippers of the large 

 claw, producing a sound resembling the sudden cracking of thick glass, 

 so that one imagines that the aquarium has broken. It is well known 



Pig. 9. Cassiopea xamachana, the Jellyfish of tie Moat of 

 Fort Jefferson. Tohtugas. 



from the work of Prizbram that if the large claw of Alpheus be cut off 

 the small claw changes to a large one at the next molt. 



Dr. Stockard finds, however, that if the large claw be removed and 

 at the same time all legs of the opposite side of the body except the 

 small claw be cut off, the small claw docs not change into a large one 



