SOME COMMON OBJECTS 63 



creatures " wheel-bearers." In reality the discs do 

 not rotate, and the object of the movement of the 

 ciUa is the creation of a vortex for capture of prey. 

 When at rest, or feeding, the common rotifer 

 attaches itself to some water-plant. It can travel 

 by looping its body somewhat after the manner of a 

 caterpillar, using its foot and proboscis in place of 

 legs. 



Perhaps the most remarkable rotifer is Melicerta 

 ringens, which, although only about ^j inch in 

 length, succeeds in making tiny pellets, and building 

 them into the form of a tube for its occupancy. 

 When alarmed the rotifer retires into its tube, but 

 in feeding it extends itself, and feeds in true rotifer 

 fashion; 



Every opportimity for collecting material from 

 the seashore should be taken advantage of. The 

 reader will find some valuable assistance in this 

 work by consulting " Ponds and Rock-Pools " 

 already referred to, and also " Life by the Sea- 

 shore," by Dr. Newbiggin. Rock-pools teem with 

 minute hfe-forms, and in the clean white sand found 

 in the ripples of the beach, at high and low water 

 marks, an abundance of Foraminifera ought to be 

 discovered. Foraminifera (literally, " hole-bearers ") 

 are minute amoeba-like creatures which occupy tiny 

 shells formed from lime extracted from sea water. 

 These shells are punctured with small pores, through 

 which the animal protrodes wisps from its body, as 

 a means of swimming and catching prey. It is 

 usually the shells of these creatures that we find on 

 the beach. But the shells are very small, and while 

 we may detect some of them with a pocket lens, the 



