42 KEPTILE GALLERY. 



The DactylethridcB {Xenopus, fig. 29) of tropical Africa and the 

 Pipidm of South America are small groups which form the suborder 

 of tongueless Frogs — the former being chiefly distinguished by the 

 presence of teeth in the upper jaw, whereas the latter are toothless. 

 The Surinam Toad {Pipa americana, fig. 30) is well known for 

 its curious mode of reproduction, the eggs being placed by the male 

 in cells on the back of the female, where they remain until the 

 completion of the metamorphosis. 



Order II. CAUDATA, or TAILED BATRACHIANS. 



Elongate, lizard- or eel-like in form, with two, or, exceptionally, 

 one pair of limbs and with a tail. Short ribs are .constantly present, 

 and the vertebral centra are biconcave or opisthocoelous. Over 100 

 species are known, from Europe, Temperate Asia, North Africa, and 

 North and Central America, but they are entirely absent in the 

 Southern Hemisphere. They are arranged in four families : — 



1. Salamandrid(B. 2. AmpMumida. 3. Proteidce. 4. Si- 

 renidce. 



Fig. 31. 



Amblj/stoma tigrinum (Axolotl of Mexico). 



The Salamandridce, or Newts and Salamanders, lose their gills 

 before they reach the adult state. However, there are instances 

 occurring in various genera, of which the Axolotl (fig. 31) is the 



