478 J. H, ORTON. 



The manner of chaining in Crepidula is adapted to securing a good 

 food and respiratory current. 



The mandibles in Crepidula arc to be found just behind and a little 

 to either side of the middle of the anterior border of the roof of the 

 mouth. 



The author wishes here to express his thanks and indebtedness to 

 the Government Grant Committee for a grant out of which some of 

 the expenses of the foregoing work were defrayed. He is also grateful 

 to Dr. Allen for useful criticism. 



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