ROTIFERS. 213 



the tip of the long foot to an aquatic object. The cil- 

 iary disk consists of four parts or lobes of different 

 shapes and sizes, and the little creature also has a very pe- 

 culiar and rather complicated organ for making 

 the pellets. The whole front part of the body 

 can be folded together into a rounded mass 

 when Melicerta is frightened and retires to 

 her sheath. "When her fright is over, she 

 slowly protrudes this rounded mass from the 

 aperture, gradually spreads it open, sets the 

 cilia at work, and proceeds to eat and build. 

 The last she seems to do almost continuously. 

 As her body grows, her house must be enlarged to re- 

 ceive it. 



The ciliary disk of Melicerta will repay the most care- 

 ful study. And careful observation will be needed to 

 learn just how the three distinct currents that she makes 

 in the water are produced. One current brings food 

 particles to the mouth, where she selects the acceptable 

 morsels and passes them on to the mastax ; a second 

 current carries away the fragments for which she has no 

 use ; and the third sets in towards the little organ that 

 makes the pellets. This is a small cavity into which 

 the building material is poured, and where it is turned 

 about rapidly by the fine cilia which line it. A sticky 

 secretion is exuded that causes the particles to adhere to 

 each other, and the revolving motion gives the pellet 

 the shape of a Minie-bullet. When the latter is formed 

 to the Kotifer's liking, and all is ready for the final act, 



