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It resembles the crocodile in the extension inwards of the 

 superior maxillary bones over the top of the skull to the nasal 

 bone, constituting with it a continuous roof to the nasal cavities, — 

 while in the frog there is a wide interval between these bones. 

 The broad and almost continuous flooring, formed by the palate 

 in the roof of the mouth, indicates a nasal cavity having sub- 

 terminal nostrils, separated from the cavity of the mouth, and 

 with their posterior openings far behind the nasal apertures, as in 

 the crocodile, — while, in the air-breathing Batrachians, the nasal 

 passage is very short, the internal apertures piercing the anterior 

 part of the palate. 



It resembles Batrachians in having a row of small teeth extend- 

 ing transversely across the anterior extremity of the palate bones, 

 consisting (in the English fossils) of three median small teeth, 

 and two outer large ones on each side ; and in having a longitud- 

 inal row of small, equal-sized teeth, continued backward along the 

 exterior margin of the palatine bone, concentric with the maxillary 

 teeth, as in the Amphiuma — teeth of both of which series are 

 recognized in the cast. In the maxillary teeth, it resembles the 

 crocodile, having a large tusk on each side in each jaw, from 

 which the teeth grow smaller as they go backward ; there are 

 teeth anterior to these tusks, which are implanted on the outer edge 

 of the alveolus, every alternate socket being empty to receive those 

 of the opposite jaw. Pictet mentions the original of this cast as 

 having more than one hundred teeth in all, seven of which are 

 in the intermaxillary bone. Owen mentions, as characteristic of 

 the Labyrinthodon, a row of small teeth, as in fishes, anterior 

 and external to the larger teeth. 



Other parts of the skeleton, as described by Owen, show 

 mingled Batrachian and Crocodilian characters. The symphysial 

 extremity of the lower jaw is abruptly bent inwards, and the 

 angular piece is broad, extending forwards to near the symphysis, 

 as in Batrachians ; the long and slender ramus resembles most 

 nearly that of Amphiuma. The bodies of the vertebroe present 

 biconcave articular surfaces ; the superior arch is anchylosed to 

 the centrum ; the articular surfaces slope in a parallel direction, 

 obliquely to the axis, indicating an habitual inflexion of the spine, 

 as in the frog. The strength and direction of the transverse 



