20 



FIRST BOOK OF ZOOLOGY. 



eggs will hatch out tiny snails, and these will attain half 

 their mature size the first season. 



a 



FIG. 



a, Eggs of Land Snail; &, Young Snail just hatched; c, Youug Snail somewhat 

 advanced: b and c are magnified. 



19. If the pupil will also collect a lot of fresh- water air- 

 breathing snails, and keep them alive, they will deposit their 

 eggs upon the sides of the glass jar in which they are con- 

 fined. These eggs will be oval in shape, and transparent, 

 and will be inclosed in a transparent, jelly-like substance. Fig. 

 14, H, represents the appearance of a cluster of these eggs. 



Fig. 24 shows a cluster of eggs with the appearance of 

 two eggs highly magnified, showing the young snails as they 

 appear within the egg. 



a 



FIG. 24. a, Cluster of Eggs of a Fresh-Water Snail; &, c, Eggs enlarged, showing the 



young Snails within the Eggs. 



With the aid of a magnifying-glass, the eggs may be 

 watched from day to day, and the young snail can be seen in 

 its various stages of growth. 



