§11. THE LABYRINTHODON. 551 



rinthine folds of the external layer of cement towards the 

 pulp cavity ; and within these inflections, the dentine, or 

 tooth-ivory, is similarly disposed. Transverse sections, 

 therefore, display the most beautiful interfoldings of the 

 two substances; and as the fossils are generally deeply 

 coloured by iron or manganese, they exhibit under a slightly 

 magnifying power, an extremely interesting appearance ; * 

 this peculiarity of organization suggested the name assigned 

 to this genus of fossil Batrachians.f 



From the structure of the cranium, it appears that the 

 Labyrinthodon, of which there are five species, had sub- 

 terminal nostrils leading to a wide and shallow nasal cavity, 

 separated from the cavity of the mouth by a broal and 

 almost continuous horizontal palatal flooring. It is, there- 

 fore, inferred that these reptiles breathed air like the 

 crocodiles, and were probably furnished with well-deve- 

 loped ribs : thus the first representatives of the Batra- 

 chians, of which we have any indication, belong to a higher 

 condition of structure than any now known to exist .J The 

 gigantic Wirtemberg Batrachian must have borne the same 

 relation in magnitude to the diminutive existing frog-tribe, 

 as the extinct colossal Iguanodon to the recent Monitors 

 and Iguanas. 



Claydyodon, — Several detached pointed, trenchant, re- 

 curved teeth, the crowns of which are an inch long, and 



* The teeth of the recent Lepidosteus, or Stony-gar, a fish that 

 inhabits the rivers of America, have a similar structure, but less com- 

 plicated than in the Labyrinthodon. See " Medals of Creation," vol. ii. 

 p. 651. 



t See " Medals of Creation," vol. iv. PL VI. fig. 3. 



t " As in the existing diversified order of Batrachia, one family 

 (Perrenibranchiata) represents Fishes: — a second (Ceciliadce), Ser- 

 pents : — a third genus (Pipa), Turtles : and a fourth (Salamandra), 

 Lizards : — so would the now lost Labyrinthodons have formed repre- 

 sentatives of the highest order, viz. the Crocodilians." — Prof. Owen, 

 in Brit. Assoc. Rep. 1841, p. 197. 



