41. Amniotes are tetrapods ( descendants of four-limbed and backboned animals ) that are characterised by having an fetus.42. Although they bear similarities to those of amniotes , the tarsal bones of diadectids are poorly ossified and loosely connected. 43. This allowed amniotes to lay eggs on dry land, while amphibians generally need to lay their eggs in water. 44. In amniotes , most of the former opisthonephros became the epididymis, and the archinephric duct became the vas deferens. 45. The first amniotes are known from the early part of the baphetids, which have left no extant surviving lineages. 46. Reptiles have relatively few nephrons compared with other amniotes of a similar size, possibly because of their lower metabolic rate. 47. Inhaling with the ribs was either primitive for amniotes , or evolved independently in at least two different lineages of amniotes. 48. Inhaling with the ribs was either primitive for amniotes, or evolved independently in at least two different lineages of amniotes . 49. Very early in the evolutionary history of amniotes , basal amniotes sauropsids, both of which persist into the modern era. 50. Very early in the evolutionary history of amniotes, basal amniotes sauropsids, both of which persist into the modern era.
