302 



CLASS AMPHIBIA. 



bj> a ductus Botalli. In the larva there is a slender anterior 

 arrh (1st branchial), which disappears. 



The urinogenital organs are on the usual type (p. 293). 



Gymnophiona are found in Central and South America, 

 Equatorial Africa, India and the Malay Archipelago. They are 

 not found in the West Indian islands or in Madagascar. They 

 burrow in the surface soil in damp places and near streams. 

 Their eyes which may usually be discerned through the skin are 

 of lise only in enabling them to avoid the light. In the male 



FIG. 173. Skull of IcJithyophis qiutinosa (from Gadow. after Sarasin). A from the side ; B from 

 below ; C from above. A posterior process of the os articulate ; Ca carotid foramen ; 

 Ch internal narial opening ; F frontal ; J jugal ; Lo exoccipital ; MX maxilla ; N nasal ; 

 No external narial opening ; orbit ; P parietal ; Pa palatine ; Pm premaxilla ; Pof post 

 frontal ; Prf prefrontal ; Pt pterygoid ; Q quadrate ; 5 squamosal ; St stapes (columella 

 auris) ; T tentacular groove ; Vo vomer ; X foramen for vagus nerve. 



the cloacal walls are eversible and when protruded form an 

 intromittent organ by which sperm can be transferred to the 

 cloaca of the female. Fertilisation therefore is internal. Some 

 species, e.g. Typhlonectes compressicauda, Dermophis thomensis, 

 are viviparous ; others are oviparous. The eggs are of con- 

 siderable size (in Ichthyophis qlutinosa 9x6 mm.) and are 

 meroblastic. In the viviparous forms, so far as is known, the 

 young are born fully developed and there is no larval stage. 

 In the oviparous forms there seems to be some difference in this 



