202 AMPHIBIA 



also to defend the brood. Autodax derives its name from its 

 formidable teeth, and it has been observed to use them when 

 disturbed, snatching fiercely at intruders. The spherical eggs 

 measure about six millimetres in diameter and are firmly 

 anchored to the earth or bottom of the hole by a narrow 

 peduncle about eight millimetres long, of the same substance 

 as the gelatinous capsule surrounding them, these peduncles 

 converging towards the basal point of attachment of the 

 bundle. The embryo is quite distinct, at first, from the large 

 yolk sphere; it has large lobate gills (allantoic gills) quite 

 different from the fringed gills of newts and salamanders. 

 When the young emerges from the egg-capsule, the gills at once 

 wither away and the little Autodax enters the world in the per- 

 fect condition, measuring thirty-two millimetres in length. 

 The young are believed sometimes to remain for a long time 

 in the hole with their parents. 



( i) B. Salamandrella keyserlingii, a very small aquatic sala- 

 mander from Siberia, deposits its eggs in a gelatinous bag, 

 fifteen centimetres long, attached at one end to aquatic plants, 

 just below the surface of the water. This bag is more or less 

 sausage-shaped and contains fifty to sixty small eggs ; the 

 larvae when hatched drop to the bottom of the bag and are 

 liberated in a moderately advanced state of development, 

 measuring ten millimetres, and provided with large external 

 gills but limbless. 



(2) A. Plethodon, a genus of small terrestrial salamanders in- 

 habiting North America, rears its brood on land. In P. cinereus, 

 the eggs are laid in small packages of about five, beneath stones, 

 and the mother remains coiled around them. The larva sub- 

 sists on a large spherical yolk and does not leave the gelatinous 

 capsule of the egg until after the loss of the gills, which are 

 long and branched, and three in number. P. oregonensis has 

 similar habits. A female was found under a decaying log in 

 a wood in California, tending three eggs, similar in size and 

 form to those of Autodax. They were covered with a thin 

 gelatinous coating, causing them to stick together. When 

 placed in a jar, the salamander again took charge of the eggs, 

 lying beside them and holding them in a loop of her prehensile 

 tail. Dissatisfied with their position and surroundings, she 

 moved the eggs from place to place in the jar, always holding 



