The eggs may be found in these ponds at this time. They are attached to long strings of jelly which entwine among grasses and other objects in the ponds. (Frogs' eggs are in masses of jelly, not in strings.) Place some of the eggs in a jar of water and set the jar in the window of the school-room. A great mass of eggs is too much to put in a jar, a few dozen eggs in a pint of water will be more likely to develop. The water in the jar should be changed twice a week. ~Observations.~--The light and dark areas of the eggs, the dark area gradually increasing in size; the increase in the length of the egg; the gradual change of the dark area into the general shape of a tadpole with head and tail, the first appearance of the gills, the separation from the jelly, the movement by means of the tail, the disappearance of the gills, the growth of the hind legs and, later, of the forelegs, and the disappearance of the tail. ~Questions and Observations.~--What is the use of the dark colour of the area from which the tadpole is formed? Explain the uses of the strings of jelly. Describe how the tadpole swims. Upon what does the young tadpole feed? What is the advantage of external gills at this stage in the tadpole's life? ~Later Observations.~--The disappearance of the gills, the budding out of the hind legs and, later, the forelegs. While the legs are growing out, the tail gradually becomes smaller, at the same time the shape changes to that of the adult toad with a broad body and large mouth and eyes. ~Questions.~--What movements has the toad which the tadpole did not have? What makes these movements possible? Why is the mouth of the toad better suited to its manner of life than the small mouth of the tadpole would be? Of what advantage to the tadpole was the smooth outline of its body, and why is the rougher outline of the toad's body better suited for the life of the latter? Why would gills be unsuitable for the life of the toad? _To the teacher._--From the dark area of the egg the tadpole develops, the dark colour absorbs the sunlight, and this causes growth. The jelly holds the eggs up so that the sun can reach them and it also keeps them from being swept away by the water. The tadpole is very small, and external gills are needed to keep it in very close contact with the water. The tail does not drop off, the substance in it is absorbed into the body of the growing toad to serve as nutriment. Since all the changes in the development of the toad from egg to adult form take place in about one month, this comparatively rapid development makes the life history of the toad particularly suitable for observation work. The development of the eggs of the frog or newt may be studied from preparations made in precisely the same way as those for the study of the development of the toad.