606 AMPHIBIA. 



Sub-order Aglossa. Tongueless ; the Eustachian tubes have a 

 common median aperture into the pharynx. The Surinam 

 toad (Pipa amerzcana), and the allied African genus 

 Xenopus. 



Order URODELA or CAUDATA 



The tail persists in adult life ; the larval gills and gill- slits may also 

 persist ; the limbs are weak when compared with those of Anura, and 

 the hind pair may be absent. There are numerous (37-98) vertebrae, 

 amphiccelous or opisthoccelous. 



Family I. Amphiumidae. The N. American Amphiuma, with two 

 pairs of rudimentary legs, with a slit persisting in adult life 

 as a remnant of the gilled state ; Cryptobranchus maximus^ 

 the largest living Amphibian, found in Japan and Thibet, 

 attains a length of over 3 ft. 



Family 2. Salamandridae. Salamandra maculosa and S. atra, both 

 European, both viviparous : the usually oviparous newts 

 Triton or Molge of which Triton alpestris becomes 

 sexually mature while still larval (padogenesis). Desmognathus 

 fusca, the common lungless water salamander of the United 

 States, lays its eggs in a wreath which the female twines 

 round its body. The N. American Amblystoma, with its 

 sometimes persistent larval form the Axolotl, formerly thought 

 to be a different species. 



Family 3. Proteidae. With persistent gills. Several species of 

 Proteus inhabit the caves of Carinthia and Dalmatia. There 

 are two pairs of limbs. The eyes are degenerate and the skin 

 white, as we should expect in cave- animals. Two species of 

 Necturus (or Menobranchus} occur in N. American rivers and 

 lakes. 



Family 4. Sirenidse. Two extant genera, Siren and Pseudobranchus, 

 both N. American, both with persistent gills, and only 

 anterior limbs. Papillae in the lower dermic layer in Siren, 

 hidden by looser superficial dermis and epidermis, look like 

 vestiges of ancestral scales. 



Order GYMNOPHIONA or APODA 



Worm-like or snake-like forms, subterranean in habit; without 

 limbs or girdles ; with extremely short tail ; with dermic calcified 

 scales concealed in transverse rows in the skin ; in at least some forms 

 (Hypogeophis} external gills are present in the very young stages, but 

 disappear before hatching ; there may be no larval stage ; if there is, the 

 respiration is pulmonary. There are many other striking peculiarities : 

 the eyes are small, covered up, and functionless ; there is no 

 tympanum or tympanic cavity ; there is a peculiar protrusible 

 tentacle in a pit behind the nostril ; there are only two pairs of 

 aortic arches (systemic and pulmonary). The notochord is lai-gely 

 persistent ; the vertebrae are amphiccelous ; the frontals are distinct 



