The literal meaning of Gymnophiona is "naked snake". In Greek, gymnos means "naked" and opineos means "snake".
The animals included in this order are caecilians. These animals are elongate, limbless and burrowing, having small dermal scales on the skin and with many vertebrae and long ribs. Small eyes are present and many species are blind. They live in tropical forests of South America, Africa, India, and Southeast Asia.
Woodland salamander belongs to genus Plethodon and they lack lungs. They have internal fertilization, i.e. the eggs are internally fertilized.
The female recovers a packet of sperms, which are deposited by the males over a stick or leaf of her cloaca. The sperms are then stored in the female body and used for fertilizing her eggs before laying them.
The female lays eggs in small clusters, which look like grapes under the tree logs, which are soft and moist. In some species, the adults become the guardians of the eggs. The salamanders have direct development and they emerge as small forms of adults bypassing the larval stage.
Hence, woodland salamanders have internal fertilization and direct development.
The integument of the frog consists of two layers- outer stratified epidermis and inner spongy dermis. The epidermis contains two types of glands, mucous and serous glands. Mucous glands secrete mucous to protect the skin and whitish, watery poison is secreted by the serous gland which is used to irritate the predators.
The various colors produced by the skin of the frog are due to the presence of special pigment cells known as chromatophores, located in dermis. There are three types of chromatophores which impart different colors to the frog.
• Xanthophores -yellow, orange and red color.
• Iridiophores -silvery light
• Melanophores -black or brown