606 AMPHIBIA, 
Sub-order Aglossa.—Tongueless; the Eustachian tubes have a 
common median aperture into the pharynx. The Surinam 
toad (Pipa americana), 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. 
Family 1. Amphiumide.—The N. American Amphiuma, with two 
pairs of rudimentary legs, with a slit persisting in adult life 
as a remnant ofthe gilled state; Cryptobranchus maximus, 
the largest living Amphibian, found in Japan and Thibet, 
attains a length of over 3 ft. : } 
Family 2. Salamandridse.—Sal/amandra maculosa and S. atra, both 
European, both viviparous; the usually oviparous newts 
—Tritton or Molge—of which Triton alpestris becomes 
sexually mature while still larval (sedogenesis). Desmognathus 
Jusca, the common /umgless water salamander of the United 
States, lays its eggs in a wreath which the female twines 
round its body. The N. American Ammdblystoma, with its 
sometimes persistent larval form the Axolotl, formerly thought 
to be a different species. 
Family 3. Proteide.—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. Sirenidee.—Two extant genera, Szven and Pseudobranchus, 
both N. American, both with persistent gills, and only 
anterior limbs. Papillae in the lower dermic layer in Szrez, 
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 
1imbs or girdles; with extremely short tail; with dermic calcified 
scales concealed in transverse rows in the skin ;.in at least some forms 
(Aypogeophis) 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 « peculiar protrusible 
tentacle in a pit behind the nostril; there are only two pairs of 
aortic arches (systemic and pulmonary). The notochord is largely 
persistent ; the vertebre are amphiccelous ; the frontals are distinct 
