142 LABTKINTHODONTIA. 



Genus MASTODONSAURUS, JaBger 1 . 

 Syn. Salamandroides, Jaeger 2 . 



The type genus. Skull (figs. 31, 32) broad, with slightly concave 

 lateral borders and an obtuse muzzle ; palatal vacuities broadest 

 near the middle and far removed from the muzzle ; premaxillary 

 vacuities double and somewhat approximated ; two small perfora- 

 tions for the mandibular tusks in advance of the nares ; nares oval 

 and widely separated ; orbits oval, narrowing in front, and situated 

 some distance in advance of the parietal foramen ; lyra distinct, and 

 enclosing an elongated diamond-shaped space between the orbits 

 and nares ; frontal long, pointed in front, and entering extensively 

 into the formation of the inner border of the orbit ; squamosal, 

 postorbital, and postfrontal short. Usually from three to five 

 enlarged premaxillary teeth, lateral teeth smaller ; anterior vomerine 

 teeth parallel to those of premaxiUse ; two or more enlarged palato- 

 vomerine tusks, the palatines and vomer an chy losing together in 

 this neighbourhood. Cranial sculpture either radiating ridges and 

 grooves, or pitted. Median plate 3 (interclavicle) of thoracic buckler 

 diamond-shaped, with a long posterior spine, and no distinct lateral 

 wings ; lateral plates (clavicles) not meeting in a long suture in 

 advance of the middle one. 



Mastodonsaurus giganteus, Ja3ger\ 



Syn. Salamandroides giganteus, Jaeger 5 . 

 Mastodonsaurus giganteus, Jaeger 6 . 

 Mastodonsaurus jcegeri, Alberti 7 . 

 . • Labyrinthodon salamandroides, Owen 8 . 



Mastodonsaurus salamandroides, Plieninger 9 . 

 - Labyrinthodon jcegeri, Owen 10 . 



The type species. Length of skull varying from 0,700 to 1,000. 

 Cranial and thoracic sculpture coarsely radiate. 

 Hab. Europe (Germany n ). 



I Foss. Eept. Wiirttemberg, p. 35 (1828). 2 Ibid. p. 38. 



3 See Meyer and Plieninger, ' Beitrage Pal. Wiirttembergs,' pi. iii. ; and E. 

 Fraas, Palscontographica, vol. xxxvi. p. 85, fig. 5. 



4 Foss. Kept. Wiirttemberg, p. 39 (1828).— Salamandroides. 6 Loc. eit. 



6 Bull. Soc. Geol. France, ser. 1, vol. iii. p. 86 (1833). 



7 Beitrag z. Monograph, d. Bunten Sandsteins, etc. p. 236 (1834). 



8 Trans. Geol. Soc. ser. 2, vol. vi. p. 512 (1842). 

 Ebenda, p. 57 (1844). 



10 Odontography, pt. ii. p. 198 (1841). 



II There is no sufficient evidence in support of the alleged occurrence of this 

 species in Britain. 



