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THE POPULAR SCIENCE MONTHLY. 



ward into the digestive cavity. The larger jelly-fishes, with tentacles 

 streaming out to a length of thirty or forty feet, could easily paralyze 

 large animals. It has been suggested that some of the sudden and 

 strange disappearances of bathers may have been caused by these fear- 

 ful creatures. 



Hundreds of little air-pumps are employed by the star-fish. These 

 sucking-disks upon the under side of the flexible rays enable the ani- 

 mal to adhere with surprising power. And it can also protrude its 

 stomach to inwi-ap prey which is too large to swallow. It is thus able, 

 by turning itself inside out, to suck an oyster from its shell ; and, 

 having an especial fondness for these mollusks, it makes great havoc 

 among the oyster-beds. 



The tongue is the prehensile organ of the univalve mollusks. 

 Being covered with rows of toothed plates it acts like a rasp, or can 

 be protruded beyond the head to serve as a drill. The vegetable- 

 feeding snails have also a bony plate in the roof of the mouth to aid 

 in cutting. The common garden-snail has not less than 28,000 teeth 

 on its strap-shaped tongue. These mollusks, and all animals hereafter 

 mentioned, have the superior power of vision which, enabling them to 

 discover food or pursue their prey, is of the greatest aid in getting 

 food. The other senses are also aids to prehension. 



Common Poulpe {Octopus vulgaris). 



The devil-fish, so called, the highest of mollusks, is possessor of an 

 apparatus which for terrible efficiency could hardly be surpassed. Its 

 prey is seized by eight long " arms " which surround the mouth, and 

 the'grasp is assured by rows of sucking-disks on the inner side of these 

 arms. Indeed, these diminutive air-pumps hold so firmly that an arm 

 will sometimes tear from the head. Some species have in addition 

 two other arms equaling the body in length, which are commonly 

 folded beneath the head, out of the way. As the creature nears its 

 intended prey, these two long arms are quickly projected and seize the 



