Page "Amphibian" Paragraph 74

The eggs of amphibians are typically laid in water and hatch into free-living larvae that complete their development in water and later transform into either aquatic or terrestrial adults.

In many species of frog and in most lungless salamanders ( Plethodontidae ), direct development takes place, the larvae growing within the eggs and emerging as miniature adults.

Many caecilians and some other amphibians lay their eggs on land, and the newly hatched larvae wriggle or are transported to water bodies.

Some caecilians, the Alpine salamander ( Salamandra atra ) and some of the African live-bearing toads ( Nectophrynoides spp.

) are viviparous.

Their larvae feed on glandular secretions and develop within the female's oviduct, often for long periods.

Other amphibians, but not caecilians, are ovoviviparous.

The eggs are retained in or on the parent's body but the larvae subsist on the yolks of their eggs and receive no nourishment from the adult.

The larvae emerge at varying stages of their growth, either before or after metamorphosis, according to their species.

The toad genus Nectophrynoides exhibits all of these developmental patterns among its dozen or so members.