BATRACHIA. 



323 



appendages. There are dermal flaps around the upper lip, and the eyes are minute. 

 The feet are broadly webbed. The color is leather brown, paler below, with some- 

 times a black stripe along the middle of the belly. 



The habits of this extraordinary animal during the reproductive season are well 

 known. The eggs are transferred by the male to the back of the female, to which 

 they adhere, and where they are impregnated; their presence excites increased activ- 

 ity in the skin, it thickens, and is gradually built up around each egg, which it at length 

 nearly encloses in a well-defined pouch; this process of investment has been com- 

 pared by J. Mtlller and others to the inclusion of the mammiferous ovum by the 

 deciduous membrane of the uterus. The opening which is left after the pouch is 



Fig. 193. — Pipa amerlcana, Surinam toad. 



formed is at length closed up by an operculum, and thus the egg is shut off from all 

 direct communication with the air. 



Professor Wyman describes the growth of the young Pipa as follows : " Of the 

 eight specimens which I have examined, two were destitute of eggs in the back, and 

 the skin of these presented a uniform surface throughout, covered, as is usual, with 

 conical papillae. One of them I ascertained by dissection to be a female, the ovaries 

 being well filled with eggs. In the backs of all the others, ova existed in different 

 stages of development, the number of egg-sacs varying in different specimens from 

 forty to one hundi-ed and fourteen. 



