366 MOSTLY MAMMALS 



and the third to Phyllobates), to which water is essential 

 while in the tadpole stage, adopt the plan of carrying their 

 young attached to their backs (either by means of suckers 

 or of a viscid secretion), and are thus enabled to transport 

 them to another pool when occasion arises. In the case 

 of the genus last mentioned, it is the father frog on whom 

 the burden of carting about his family falls, but in the 

 other instance it is not known to which sex this duty is 

 entrusted. A frog (Arthrolepis seychellensis) from the 

 Seychelles is likewise in the habit of carrying its young 

 on its back, but in this case the purpose of the arrange- 

 ment is not to transport them from one pool to another, 

 but merely to protect them during development, which 

 takes place on land, the tadpoles breathing by means of 

 lungs. 



The Coqui frog (Hylodes martinicensis) of the West 

 Indies affords, however, the best instance of the manner 

 in which these reptiles can develop without resorting to 

 the water at all. In this species the eggs are laid on 

 the leaves of plants in damp situations, the female parent 

 remaining near by on guard until they hatch. This 

 takes place in about a fortnight after deposition, but instead 

 of tadpoles, perfect little frogs make their appearance in 

 the world, all the transformations taking place within the 

 egg. A Peruvian species of the same genus (Hylodes 

 lineatus) exhibits a precisely similar mode of development; 

 and the same is the case with the curious Solomon Island 

 frog (Rana opisthodon). 



In conclusion, mention must be made of the tadpole of 

 a South African frog (Dactylethra capensis), not on account 

 of any peculiarity in its mode of development, nor on 

 account of its form (although this is strange enough), 

 but from the curious circumstance that it alone, among 



