THE MICROSAURIAN FAMILY TUDITANIDyE. IO3 



of longitudinal fluting. The arrangement of the mandibular elements recalls in a 

 striking way the mandible of Eryops megacephalus Cope as figured by Branson (49). 



MEASUREMENTS OF THE MANDIBLE PROVISIONALLY ASSOCIATED WITH ERPETOSAURUS TABULATUS COPE. 

 (No. 8542 G, American Museum of Natural History.) 



mm. mm. 



Length of mandible 32 Length of one of the posterior teeth 1.25 



Posterior width across surangular 6 Width across base of same tooth 50 



Width of dentary 3 Length of long anterior tooth 2 



Width of jaw at tip 1.5 Width of same tooth at base 75 



Another specimen of this same species is 8550 G, of the American Museum. 

 Linton, Ohio, Coal Measures. 



PALATE OF ERPETOSAURUS TABULATUS COPE. 

 MOODIE, Bull. Amer. Mus. Nat. Hist., xxvi, pp. 352-354, pi. Ixi, fig. 2, 1909. 



The specimen is half a cranium with its impression. It is referred to Erpeto- 

 sdiirns on the basis of the sculpturing of the mandible and the posterior table of the 

 skull. On the surangular there is seen the rugosity which is common to other mem- 

 bers of the genus. The characters presented are those of Erpetosaurus tabidatus 

 Cope, but the reference is rather uncertain. 



The specimen is unique among the known American material in showing the 

 structure of the palate. Jaekel (347) has figured and described the palate of 

 Diceratosaurus punctolineatus Cope from the Linton beds. The present palate differs 

 from that species only in the enlarged ectopterygoid and the smaller palatine. 



The parasphenoid, in the present form, does not differ from that element in other 

 Paleozoic Amphibia. Its form is slender, arising from an enlarged base and sepa- 

 rating the pterygoids by its own width. The exoccipitals are probably represented in 

 the specimen and they have been indicated in the drawing (fig. 22 C). They are 

 rather large and extend some distance under the base of the skull to unite anteri- 

 orly with the pterygoids, a very unusual arrangement. The pterygoids are elongate 

 elements and are bounded anteriorly by the vomer and laterally by the ectoptery- 

 goid. The vomer shows no evidence of being toothed, although it may have been so 

 anteriorly. The same may also be said for the palatines. The relations of the ecto- 

 pterygoids are rather unusual for the Amphibia, especially in the posterior exten- 

 sion of the element. The bone lies all along the side of the pterygoid and anteriorly 

 projects forward between the pterygoid and the palatine. In this unusual posterior 

 projection the ectopterygoid has almost obliterated the infratemporal foramen, 

 which possibly may be still represented by the triangular space between the bases 

 of the pterygoid and the ectopterygoid. The anterior palatine foramen (internal 

 nares) lies between the anterior ends of the palatine and the vomer, its usual rela- 

 tions in the labyrinthodonts. The foramen may be recognized as the rounded 

 depression slightly anterior to the palatine. 



The mandible is rather heavy and is coarsely sculptured with radiating grooves 

 and ridges. The character of the teeth can not be determined, save to say that they 

 were present. The posterior end of the mandible projects somewhat beyond the 

 quadrate angle of the skull. 



