Anamniotes

. The group is characterized by retaining the primitive vertebrate condition in several traits: • Absence of an amnion • Absence or rudimentary condition of the allantois • Permeable skin allowing diffusion of water and gases directly through the skin. • Presence at some period of life of gills. ==History of discovery==

The features unifying the anamniotes was first noted by Thomas Henry Huxley in 1863, who coined the phrase Ichtioid or Ichthyopsida ("fish-face") for the group. It is a taxonomic classification just below the level of Vertebrata, though Huxley presented the Ichthyopsida as an informal unit and never ventured to forward a Linnaean rank for the group. The term Ichthyopsida means fish-face or fish-like as opposed to the Sauropsida or lizard-face animals (reptiles and birds) and the mammals. The group representing an evolutionary grade rather than a clade, the term anamniote is now used as an informal way of denoting the physical property of the group, rather than as a systematic unit. ==References==