958 MR. D. M. S. WATSON ON A 



tlie front of the jaw ; in front it ends freely in a point, its lower 

 border articulates with the angular and snrangular, and its 

 upper border witli the epicoronoids ; the inner surface of the 

 bone is covered with a shagreen of small denticles. 



The epicoronoids are two small bones lying between the upper 

 edge of the coronoid and the dentary. The posterior is a shoi't 

 bone forming the front of the suprameckelian A^'acuity, and 

 bearing two large teeth and the pits for their replacing teeth. It 

 is separated from the anterior epicoronoid by a large round 

 foramen. The anterior bone beai's one tooth and its replacing 

 tooth-socket. 



The jaw of MegalicJdhys differs slightly from that of Rhizodus, 

 Rhizodopsis, etc., in there being only three bones besides the 

 dentaiy on the outerside of the jaw, instead of four, and only two 

 epicoronoids instead of thi-ee. 



Comparison of this jaw with that of "Zo.rom7?z«" will, I think, 

 justify the nomenclature used here, even the direction of overlap 

 of the bones being the same in the tw^o types. 



Systematic position of Batrachiderpeton. 



The classification of the smaller stegocephalian Amphibia, so 

 abundant in the Coal-Measiu^es and Permian Rocks of Europe 

 and North America, is in such confusion, to which some 

 recent work has added, that it is at present only possible to 

 proceed by reference to individual specimens which have been 

 well described. The difficulty of identifying species and the 

 rashness with which genera often founded on very imperfect 

 materials have been extended to include other types often of 

 veiy distinct structure, combined with the great technical 

 difficulties of working on small and often badly-preserved 

 animals, make any wide divisions at present of very doubtful 

 value. 



Batrachiderpeton in the forward position of its orbits and the 

 great " corn via " at once recalls Ceraterpeion, originally desci'ibed 

 by Huxley from Kilkenny. The type-specimen of this latter 

 genus is badly preserved, so that the sutures of the cranial roof 

 are not clearly shown, although it seems probable that the 

 apparent sutures are real, in which case there are many resem- 

 blances between the two types. 



To the type-species Ceraterpeton galvani two other specimens 

 have been assigned — Ward's specimen from North Staffordshire 

 described by 0. W. Andrews, and a specimen from Kilkenny 

 figured by A. Smith Woodward. These two specimens agree 

 extremely closely in size and in the shape of the skull, but they 

 differ from the type in being only about one-half of the size and 

 in having a narrower skull. In the Hancock Museum there are 

 three specimens closely similar from the Low Main seam of 

 Newsham, one of which is the type of Hancock and Atthey's 



