LIMBLESS BATRACHIANS 271 



in the earth, on the banks of small rivers or ponds. Soon 

 after being laid they adhere together, forming a mass 

 round which the female coils herself for their protection. 

 The gelatinous envelope of the egg is thick and tough, 

 and the embryos, w^hich are provided with extremely long 

 external gills, three on each side, are only released at an 

 advanced stage of their development, and only after the 

 external gills have been lost, the larva being then provided 



Fig. 25. — Icthyophis glutinosiis, female with eggs. 



(^After Sarusin.^ 



with an opening on each side, behind the head, the 

 spiraculum. During their aquatic life the eyes are well 

 developed ; the tail, although short, is crested above and 

 below, and the head resembles that of a Urodele. 



The development of Hypogcophis, of the Seychelles, 

 corresponds to that of Icthyophis ; the larvae, however, do 

 not go to the water, the young leaving the egg in the 

 perfect form, leading, as soon as released, the burrowing 

 existence of their parents. 



Typhlonectes and SiphonopSy of South America, and 

 Dermophis thomensis, of West Africa, do not lay eggs, the 



