l8o WONDERS OF POND LIFE. 



ing amid a thousand perils ; here a playful shiner 

 swims up noiselessly to nibble, but the stone mason 

 suddenly quits his labor and goes in. The danger 

 being over, it cautiously shows its head again and 

 resumes the occupation of clutching with its man- 

 dibles and feet small grains of sand, actually turn- 

 ing each grain over and over, as the workman in 

 building a stone wall will turn a rock in his hands 

 to decide its best fitting-place. Then with water- 

 proof cement (saliva) it places grain after grain 

 around the end of the case until it is completed. 

 In this little round stone house it crawls along on 

 the bottom of the tank, comparatively safe, proving 

 too much even for a fish's curiosity, but at the 

 expense of a very heavy burden, and, when in its 

 native stream, eking out a most precarious exist- 

 ence of two years. 



The other species under our observation is quite 

 small and not so clumsy. Its house is made of 

 short, narrow strips of grass, pasted together by 

 the animal, and arranged in regular spirals. From 

 it appear the head and two pairs of legs, by Avhich 

 it propels itself through the water, always main- 

 taining a perpendicular position, and waltzing up 

 to the surface in a most comical manner. We will 

 rob this fellow of his home. The creature offers 



