io6 TYPES OF ANIMAL LIFE 



greatly, though very naturally, misunderstood. The skin 

 of the female's back, as the time for egg-laying approaches, 

 thickens greatly and becomes of quite a soft and loose 

 texture. The male, as soon as the eggs are laid, takes 

 them up and imbeds them in this thick, soft skin, which 

 closes over them. Each egg so enclosed then .undergoes 

 the process of development to the end, so that instead of 

 coming forth as a tadpole, each young one comes forth as 

 a very small but fully formed toad. Here again the 

 young never develop gills. When the young have 

 gone forth, a little pit or depression marks the spot 

 where each egg was developed, and as many as 120 of 

 these pits have been counted on the back of a single 

 female. 



But a yet more singular mode of development takes 

 place in another American frog which comes from Chili, 

 and is known as Darwin's lihinoderma. 



Here nothing special is to be seen in the female, but in 

 the male a large sac or pouch is present and extends 

 beneath the skin under the whole surface of the belly 

 and lower jaw. No external opening into it is to be found 

 until we open the frog's mouth, and then we find two 

 apertures, which lead directly into it, placed on the floor 

 of the mouth, one on either side of the tongue. There 

 are many animals, the males of which will eat their own 

 offspring if they get the chance. They, however, perform 

 the act for their own pleasure or profit. Not so Darwin's 

 Hhinodnrwa. He takes his wife's eggs, indeed, into his 

 mouth, but it is for their good,- not his. He does not 

 swallow them into his stomach, but passes them through 

 the apertures on either side of his tongue into his great 

 ventral pouch. There they develop and become lively 

 young frogs, to the questionable comfort of -their ex- 

 emplary sire. When sufiiciently developed, they make 



