Amongst the amphibians, a few genera referred to the Seymouriamorpha show many developments that suggest they were evolving towards the reptilian condition. Some palaeontologists believe that these animals have attained the ‘half-way’ stage in the evolution of the first reptiles. Others, however, including A. L. Panchen, claim that Kotlassia prima and its relatives retain a lateral-line system and a tadpole stage in the early part of their life cycle. Kotlassia prima, known from the Upper Permian, is one of the last survivors of this important stock. See also seymouria.