300 We Go A-Sponging [FOURTH WEEK 



average person, whatever his profession, cannot fail to 

 be interested. 



Many volumes have been written on the microscopic 

 life of ponds and fields, and in a short essay only a hint 

 of the delights of this fascinating study can be given. 



Any primer of Natural History will tell us that our 

 bath sponges are the fibrous skeletons of aquatic animals 

 which inhabit tropical seas, but few people know that in 

 the nearest pond there are real sponges, growing some- 

 times as large as one's head and which are not very dis- 

 similar to those taken from among the corals of the 

 Bahamas. We may bring home a twig covered with a 

 thick growth of this sponge ; and by dropping a few grains 

 of carmine into the water, the currents which the little 

 sponge animals set up are plainly visible. In winter these 

 all die, and leave within their meshes, numbers of tiny 

 winter buds, which survive the cold weather and in the 

 spring begin to found new colonies. If we examine the 

 sponges in the late fall we may find innumerable of these 

 statoblasts, as they are called. 



Scattered among them will sometimes be crowds of 

 little wheels, surrounded with double-ended hooks. These 

 have no motion and we shall probably pass them by as 

 minute burrs or seeds of some water plant. But they, too, 

 are winter buds of a strange group of tiny animals. These 

 are known as Polyzoans or Bryozoans; and though to the 

 eye a large colony of them appears only as a mass of thick 

 jelly, yet when placed in water and left quiet, a wonderful 

 transformation comes over the bit of gelatine. ..." Per- 

 haps while you gaze at the reddish jelly a pink little pro- 



