200 THE INFANCY OF ANIMALS 



female carries the eggs in her mouth ; and the second is 

 that of Darwin's Frog {Rhinoderma darwini), the only 

 frog discovered by Darwin in Chili during his memorable 

 trip as naturahst on the voyage of the Beagle. The male 

 has a great pouch under the throat, opening by two slits 

 into the mouth ; and this pouch, during courtship, is used 

 as a voice organ, producing sounds like a Httle bell. But 

 the sounds cease as soon as the eggs appear, for he 

 thrusts them into his pouch, through the apertures just 

 referred to ; and here they hatch. To provide for their 

 accommodation, and they range from twelve to fifteen 

 in number, the pouch is now enormously enlarged, 

 extending backwards under the belly to the groin, and 

 upwards on each side almost to the backbone ! In 

 the chamber thus formed the tadpoles lie, and here 

 they seem to remain, fasting, until they emerge as young 

 frogs. At any rate, in tadpoles which have so far been 

 examined, no horny jaws and no gills have been found :■ 

 but the intestine was filled with the remains of the yolk 

 of the egg from which they were hatched. 



A contrast has already been drawn between the young 

 of the frog tribe and those of what we call the " tailed 

 Batrachia " — the newts and salamanders. Now we pro- 

 pose to refer to one or two of the more remarkable features 

 which these present in regard to their early history. And 

 with them we shall also consider the infantile and early 

 developmental stages of certain other amphibia known as 

 the " Ccecilians," of whose very existence most of us have 

 never heard. These creatures form a race apart, differ- 

 ing structurally in many important particulars from all 

 their kin. Their most conspicuous feature, externally, is 

 the total absence of limbs. They are burrowers, and 

 found only in tropical and sub-tropical countries. 



