182 THE STUDY OF FRESH-WATER ANIMALS. 



ANNELIDA. In the mud at the bottom of aquarium 

 jars may be found a slender reddish worm, known as 

 Tubifex. It belongs to the same group as the earthworm, 

 viz. Annelida, or ringed worms. 



These are only a few of the commonest inmates of 

 ponds. 



Besides these, many minute or microscopic forms of life 

 will undoubtedly be present in aquarium jars. But 

 as these require, for satisfactory observation, the use 

 of a compound microscope, they are not further referred 

 to here. 



AQUARIUM STUDIES. 



The following lines of study of aquarium animals are 

 suggested. They do not exhaust the possibilities, and 

 teachers should be able to plan others. The distribution 

 of the lessons over the different school grades will be 

 found to be indicated in the several courses which are 

 given in another part of this work. Here they are sum- 

 marised. 



1. The study of young animals. A simple study for the 

 youngest pupils, which may consist simply in watching 

 the behaviour of larvae, e.g. gnats, cadisses, water beetle 

 larvae, tadpoles, embryo trout, etc. Hints may be given 

 as to what young animals chiefly do i.e. feed, grow, move 

 about a great deal (the restlessness of growth ; excess of 

 energy resulting in play in higher animals ; play as train- 

 ing for life. But this last scarcely applies to larvae in 

 pools). 



2. The study of life-histories. For older pupils. Atten- 

 tion should be called at the outset to the large number of 

 creatures whose appearance and life are quite different 

 from those of the adult, and also to those which resemble 

 their parents. The main facts in each life-history should 



