218 The Outline of Science 



In the South American tree-frogs called Nototrema there 

 is a pouch on the back of the female in which the eggs develop, 

 and it is interesting to find that in some species what come out 

 are ordinary tadpoles, while in other species the young emerge 

 as miniatures of their parents. Strangest of all, perhaps, is the 

 case of Darwin's Frog (Rhinoderma of Chili), where the young, 

 about ten to fifteen in number, develop in the male's croaking- 

 sacs, which become in consequence enormously distended. 

 Eventually the strange spectacle is seen of miniature frogs jump- 

 ing out of their father's mouth. Needless to say we are not citing 

 but perhaps they correct the impression of amphibians as a rather 

 humdrum race. Whatever be the mental aspect of the facts, there 

 has certainly been some kind of experimenting, and the increase 

 of parental care, so marked in many amphibians, with associated 

 reduction of the number of offspring is a finger-post on the path 

 of progress. 



4 

 The Reptilian Mind 



We speak of the wisdom of the serpent; but it is not very 

 easy to justify the phrase. Among all the multitude of reptiles- 

 snakes, lizards, turtles, and crocodiles, a motley crowd we can- 

 not see much more than occasional traces of intelligence. The 

 inner life remains a tiny rill. 



No doubt many reptiles are very effective ; but it is an instinc- 

 tive rather than an intelligent efficiency. The well-known "soft- 

 shell" tortoise of the United States swims with powerful strokes 

 and runs so quickly that it can hardly be overtaken. It hunts 

 vigorously for crayfish and insect larva? in the rivers. It buries 

 itself in the mud when cold weather comes. It may lie on a float- 

 ing log ready to slip into the water at a moment's notice ; it may 

 bask on a sunny bank or in the warm shallows. Great wariness 

 is shown in choosing times and places for egg-laying. The 

 mother tramps the earth down upon the buried eggs. All is eff ec- 



