THE ZOOLOGICAL STATION AT NAPLES 



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Among the echinoderms the methods of feeding are interesting. The 

 sea-cucumber holds fast to a rock by means of the suckers at the tips 

 of its tube-feet, and, with tentacles widely expanded like the branches 

 of a tree, waits for minute crustaceans and the larvae of all sorts of 

 animals to comfortably settle themselves upon the hospitable branches. 

 Then, with the least possible motion, the sea-cucumber very gradually 

 bends a tentacle over and into the mouth, and, as it is again extended 

 one of the two small tentacles scrapes off the resting organisms. So 

 each tentacle, in rhythmical succession, takes its turn in the feeding 

 process. Some species of star-fishes have large mouths and can swal- 

 low snails and mussels whole, sometimes consuming as many as twenty- 

 five or thirty mollusks of various kinds at one meal. Other star-fishes 

 have mouths too small to receive the animals commensurate with their 

 appetites and so they simply turn their stomachs inside out, covering 

 over a clump of oysters, and thus forming a sort of external stomach 

 into which the secretion from the digestive glands is poured. When 

 the soft parts are thus dissolved and absorbed the star-fish pulls in its 

 stomach and goes on in its devastating course. The sea-urchin has an 

 apparatus known as Aristotle's lantern providing five strong teeth 

 worked by powerful muscles with which it catches live worms and 

 crabs. The sea-crawfishes, built like lobsters except for the absence 

 of the large pincers, most perfectly convey the impression of life on 

 the bottom of the sea. They seem like uncanny agents of evil as they 

 solemnly stalk about over the rocks, poking their great antennae into 

 each other's affairs and always having several claws out for a fight, 

 yet seldom engaging with one another. Some of the veterans, however, 

 have lost an antenna, or a leg, and the missing parts are being regen- 



The Palm-like Ringed Wobms. 



