188 AMPHIBIA. 



however, observed on the neck of the recently-born young, which 

 are deposited in water, large vesicles which he regarded as gills. 



Fam. Cceciliidae. Ccecilia lumbricoidea Daud., South America ; Siphonops 

 mexicana Dum. Bibr. (fig. 628) ; S. anmdata Wagl., Brazil ; Epicrium Wagl., 



Ceylon. 



The extinct Labyrinthodonta of the Triassic, the Permian, and 

 the Carboniferous formations must be regarded as a special order of 

 Amphibia. They unite in a remarkable manner the characters of 

 the Ganoids and those of the urodele Amphibians. They possessed 

 an external dermal skeleton, consisting of three broad bony thoracic 

 plates and small scutes on the abdomen, amphiccelous vertebrae and 

 peculiar folded teeth (hence the name of the group) in the Crocodile- 

 like jaws. It has also been shown that they possessed branchial 

 arches in the young state (Archegosaurus}. The footmarks of gigantic 

 animals (Chirotherium), which have been discovered in the Bunter- 

 sandstein in England and Germany (Hildburghausen), and which 

 some have ascribed to Chelonia and others to Marsupials, are pro- 

 bably due to the Labyrinthodonta. Owen has distinguished the 

 oldest forms with armoured skull as Ganocephala. Archegosaurus 

 Dechenii Goldf., Labyrinthodon Rutimeyeri Wied. 



Order 2. CAUDATA * (FRODELA). 



Elongated Amphibia with naked skin, usually ^oith four short limbs 

 and persistent tail, with or without external gills. 



The body, which is naked, ends with a long, usually laterally 

 compressed, swimming tail, and possesses as a rule two pairs of short 

 extremities far removed from one another. These limbs effect the 

 relatively clumsy movements of the animals on land, but in swim- 

 ming are used in a much more effective manner as oars. The 

 posterior limbs are completely absent only in exceptional cases 

 (Siren) while the anterior limbs remain as short stumps. 



Some Urodeles (Perennibranchiata) possess throughout life three 

 pairs of branched external gills, in addition to the lungs. Others 

 indeed cast off the gills in the course of their development, but 

 retain throughout life an external gill slit on each side of the neck 



* Daudin, " Histoire naturelle ge"n. et partic. des Reptiles," Paris, 1802 to 

 1804. 



Aug. Dume'ril, " Observations sur la reproduction dans la menagerie des 

 Reptiles du Muse"e d'hist. nat. des Axolots, etc., sur leur developpement et sur 

 leurs metamorphoses," Nouv. Arch, du Musee d'Mst. nat. de Paris, II., 1860. 



Alex. Strauch, " Revision der Salamandridengattungen," Petersburg, 1870. 



