STEGOCEPHALI. 315 



of wliich are amphibian and others reptihan. But whatever 

 view be taken on this point, it is clear that none of them can be 

 regarded as bridging the gulf between the piscine and terrestrial 

 type, for not only do they all present fairly specialised skeletal 

 features, but in all in which the extremities are known the 

 pentadactyle type of skeleton is fully developed. 



Sub-order 1. BRANCHIOSAURI. Small salamander-like animals, with 

 well developed gill arches in what are supposed to be immatvire specimens. 

 Occipital region of skull unossified. Carpus and tarsus cartilaginous. 

 Ventral scales thin and in rows. Upper Carbonifei'ous and Permian. 

 BrancMosaurus Fritsch {Protriton, Pleuronura), Lower Permian of Saxony, 

 Bohemia and France (Fig. 176) ; Pelosaurufi Credner ; Melanerpeton 

 Fritsch ; Dawsoiiia Fritsch ; Anvphibamus Cope ; Pelion Wyman ; 

 Urocordylus Huxley and Wright. 



Sub-order 2. AISTOPODA. Body long, snake-like without limbs or 

 pectoral girdle ; vertebrae amphicoelous. Upper Carboniferovas, Lower 

 Permian. Dolichosonia Huxley, Ophiderpeton Huxley. 



Sub-order .3. LABYRINTHODONTIA. The dentine of the teeth is much 

 folded, ventral armoiu" is usually present. From the Lower Carboniferous 

 to the Trias. Archegosaurus H. v. Meyer, with ventral armour, 4 fingers, 

 5 toes. Lower Permian ; Sparagmites Fritsch ; Chelidosaurus Fritsch ; 

 Actinodon Gaudry, etc. Mastodonsaurus Jaeger, the largest Labyrintho- 

 dont, the skull may attain a length of 1.25 m., Trias ; Trirnatosaurus 

 Braun ; Lahyrinthodon Owen, Keuper. Labyrinthodonts are described 

 from the Trias of S. Africa and of New South Wales. Footprints which 

 are supposed to have been made by Labyrinthodonts are fomid in the 

 Lower and New Red Sandstone of Eiu'ope, Africa and America. 

 Such footprints usually show five fingers and five toes, which is incon- 

 sistent with this view as no Labyrinthodont is known to have 5 fingers. 



The MiCROSAURiA from the Upper Carboniferous and Lower Permian 

 with Hyloplesion, Petrobates, Keratei-peton, Lepterpeton, Seeleya etc., 

 are visually placed with the Stegocephali. 



