DEVELOPMENT OF SURINAM TOAD. 581 



preserved during the whole of life, and the development of the 

 lungs is stopped at an early stage. It is one of the most curious 

 proofs of the influence of external conditions upon the develop- 

 ment of animals, that, by seclusion from light, and by being kept 

 at a low temperature, the common Tadpole may be prevented 

 from changing into a Frog, and may be made to continue to grow 

 as a Tadpole. 



524. A few of these animals, however, seem to diverge more 

 or less from these general characters in their reproduction. It 

 has been repeatedly stated that the common Toad, which is often 

 found in localities far from water, and from which it would seem 

 to be difficult for it to get at that element, will breed in such situ- 

 ations ; but these assertions are generally deficient in some points, 

 which render them inadmissible as proof. In some exotic 

 species, however, it is well known that the first development of 

 the egg takes place out of the water. An instance of this is 

 furnished by the Pipa or Surinam Toad (Fig. 341). In this 



FIG. 341. PIPA. 



ugly animal, which is found commonly in dark corners about 

 houses in Guiana and Surinam, the back of the female, during 

 the breeding season, exhibits a number of pits. The male, after 

 inpregnating the eggs, which are deposited in the usual manner 

 at the margin of the water, collects them together and presses 

 them into the pits on the back of the female, which then form 

 regular cells for their reception, covered with a sort of lid. The 

 development of the embryos takes place in these curious recep- 



