Amphibia — Labyrinthodontia. G5 
pelvic ; the feet pentadactyle. Skull with the temporal region Wall-case, 
completely roofed over by the post-orbital and supra-temporal ^ 0 - 11 * 
bones, with a parietal foramen. Teeth pointed, having a large Table-cases, 
pulp-cavity and the dentine simple or plicated. Vertebrae amphi- Not, ‘ 23 ’ 
ccelous and ossified, but a notochordal canal is often present. 
A bony thoracic buckler on the ventral aspect. Bony scutes 
frequently present on the ventral aspect of the body. Teeth are 
generally present on the palatines and vomer and more rarely on 
the pterygoids. There is generally an ossified sclerotic ring. 
Pig. 86. — Frontal aspect ot cranium 
of Capitosaurus robustus (Meyer); 
Middle Keuper (Upper Trias), near 
Stuttgart, Wiirtemberg. Letters as 
in Fig. 84. (^ nat. size.) 
Fig. 87. — Frontal aspect of the cranium 
of Metoposaurus diagnostics 
(Meyer), Upper Trias, near Stutt- 
gart. Letters as in Fig. 84. (i 
nat. size.) 
The Labyrinthodonts were frequently of large size; the 
dentine of the teeth was usually plicated ; the cranial bones were 
deeply sculptured and usually marked by numerous mucous 
canals, similar to those observed in skulls of the higher Paria- 
sauria and Crocodilia. Professor Seeley regards these groups 
as directly descended from the Labyrinthodonts. 
The Labyrinthodonts range from the Carboniferous to the 
Trias, and were especially abundant in the Permian epoch. 
One genus (Rhino saur us) persisted to Lower Jurassic times. 
One of the largest of these forms is the Alas to dons at iru s 
giganteus (Jager), from the Keuper of Wiirtemberg, the skull 
of which measures a yard in length, and broad in proportion ; 
the snout is obtuse, the nares are oval and widely separated ; 
(1189) ' 6 
