The skeletal material of Kotlassia prima, a primitive tetrapod from the Upper Permian of the North Dvina River in northern Russia, is described and figured in detail. The various specimens permit a nearly complete description except for the feet. Karpinskiosaurus secundus is a synonym of Kotlassia prima. The animal is definitely amphibian in nature although it may be regarded as a relict of the reptilian ancestors of the Reptilia. Kotlassia was as an adult a terrestrial form, in contrast to the contemporary Dvinosaurus. Seymouria may be an amphibian of the same kind.
- Received 14 June 1943.
- © 1944 Geological Society of America