260 GENERAL ZOOLOGY 



longitudinal stripes. In general the colors are suitable for 

 the activities of different kinds of individuals, and skinks 

 are therefore protected from enemies at all ages. 



There is one defect in the skink's means of defense. A 

 reptile of any kind cannot remain active at low tempera- 

 tures. During cool weather, therefore, a dormant skink, 

 if its hiding place is discovered, makes a fine meal for any 

 prowling warm-blooded animal. 



Race Preservation. Skinks, like other reptiles, are of 

 separate sexes. In the species under discussion the 

 mature males are easily recognized by their bright red 

 heads. In the northern states they mate with the females 

 in June, fertilization taking place within the female's body 

 before the shell is formed about the eggs. This is an 

 improvement over the method of fertilization prevalent 

 in amphibians, where the sperm and egg cells are usually 

 discharged into the water. When the eggs are laid, early 

 in July, segmentation has already begun. They are de- 

 posited in little cavities in the rotten wood of old stumps, 

 and the mother remains with them until they hatch (Fig. 

 99, C). In August the young skinks leave the nest~and 

 start out for themselves. 



Though the development of reptiles is similar to that 

 of amphibians, it shows greater specialization for terres- 

 trial life. A skink, or, any other reptile, always lays its 

 eggs on land, whereas amphibians usually deposit theirs 

 in water. The gills in an embryo skink are absorbed long 

 before the egg hatches and are never functional as breath- 

 ing organs. A lizard also shows greater ability to adjust 

 itself to its surroundings; in other words is less stupid 

 than a frog or toad, and even has some glimmerings of 

 intelligence. If a skink encounters a distasteful insect, 

 like a hornet or an ill-flavored caterpillar, it tries to eat 

 it the first time, but after that avoids all insects of similar 

 appearance. It can learn in its dull way that a certain 

 color or form is associated with disagreeable experiences. 



