MARVELS OF THE POND. 125 



seems inclined to associate them with insects. The 

 earlier arrangement of Huxley, in which Rotifera 

 are placed as a group of Scolecida, or lower worms, 

 such as inhabit water or are parasitic, is adopted 

 by Nicholson, and is, I think, the safest one to 

 follow at present. 



But in whatever way this zoological discussion 

 may be ultimately settled, we have evidently taken 

 a great leap from the amcebean speck of jelly with 

 scarcely any traces of permanent organs to the 

 rotifer with its comparatively high organisation. 

 We have passed through the higher protozoa, such 

 as Polycystins, the more definite modern group of 

 Infusoria (which includes creatures like the familiar 

 paramcecium), the great family of Sponges, the varied 

 forms of Corals, and on to animals like worms. 

 And yet these creatures are invisible to the naked 

 eye, and used to be classed in that omnium gatherum 

 once known as the Infusoria. What a wonderful 

 illustration we have here of the rapid advance of 

 modern science, and what a splendid testimony 

 to the value of the microscope as a handmaid to 

 scientific research ! 



Mr. Gosse prefers to call the gizzard a mastax, 

 and contends that it is really a mouth. He says 

 it consists of muscular fibre. Out of it a funnel 

 leads upwards, while a sort of oesophagus runs 

 downwards to the stomach. Inside the mastax are 

 two organs which work like hammers, and supply 

 the place of teeth. They pound down the particles 

 of food on an anvil, and prepare them for digestion. 

 All this is curious to witness, but to see these 



