IV 



LABYRINTHODONTA 83 



surface of the heiid sliows very characteristically iirrau^ed 

 grooves, which probably contained slime - canals and possibly 

 sensory organs. 



Actinodon and Uuchirosaurus are closely allied forms, chiefly 

 from the Lower Red Sandstone of France ; Gondwanosaurus occurs 

 in the Permian of India. 



Order III. STEGOCEPHALI STEREOSPONDYLI. 



These are the most highly developed members of tlie typical 

 Labyrinthodonta, characterised by their much-folded teeth, and 

 by their solid, bi-concave vertebrae. Loxomma occurs in the Upper 

 Carboniferous of England and in the Lower Eed of Bohemia : 

 TrematosaHVus, Capitosanriia, and Metojyias from the New Eed or 

 Lower Trias to the Keuper of Germany. Mastodonsaurns from 

 the Trias of England and Germany is the most gigantic 

 Amphibian known, with a skull of nearly 1 yard in length. 



Lahyri7ithodon from the Keuper of Warwickshire is one of 

 the latest members of the group. Labyrinthodont creatures have 

 also been described from the Trias of South Africa, ejj. RJiyti- 

 dosieus ; those from North America are insufficiently preserved. 



Many of these and allied genera have left their footprints in 

 slabs of Sandstone, both Lower and New Eed, in Europe, Africa, 

 and America. But although their spoors are common enough, 

 only a few can with certainty be referred to Stegocephali, e.y. 

 Haariehnites salaiiiandr aides of the Lower Eed of Germany. 

 The spoors of Chirotherinm, common in the New Eed of 

 Germany and England, for instance in Cheshire, belong to 

 unknown owners ; both the large hind feet (which measure 

 nearly half a foot in length) ami the much smaller fore feet, had 

 five digits, tlie first of which stood off like a thumb. Five- 

 fingered Stegocephali are unknown. 



There is an almost complete absence of fossil Amphibia from 

 the Upper Trias to the Oligocene. The Stegocephali as such 

 seem to have died out with the Trias. The recent Amphibia, of 

 course, must have had ancestors in the Mesozoic age. There is 

 one little skeleton, from the Wealden of Belgium, which belonged 

 to a newt-like creature, called Hylaeohatrachus croi/i. Scarce 

 fragments, described as Mryalotriton, are known from the Oligo- 

 cene of France, and Triton itself seems to be indicated by 



