124 Kansas Academy of Science. 



one or the other is absent in so many of the later reptiles may per- 

 haps explain its absence here. 



The maxilla presents but a very small surface on the superior as- 

 pect of the skull; on the side the suture separating it from the 

 jugal turns backward obliquely, as shown in fig. 1, to the hind end 

 of the dental series, passing inward obliquely to the palatines, sep- 

 arating apparently a transverse element, which is known to occur 

 in other stegocephs. The parietal is very large, articulating pos- 

 teriorly with the supraoccipital plates and the epiotics. 



The "supraoccipitals" are clearly distinguished, both upon the 

 upper and the under sides, articulating normally with the parietal, 

 epiotics and exoccipitals. On the under side the suture separating 

 them from the parietals passes inward so as to include the union 

 with the exoccipitals. There seems to be little doubt but that these 

 elements are real membrane bones, but they functionally subserve 

 the same purpose as the unpaired supraoccipital of the higher ani- 

 mals, since there is no indication here of an intervening element 

 between them and the occipitals. Most characteristic of the genus 

 and family are the greatly enlarged "epiotics," produced, as they 

 are, into such extraordinary horns. In the present species these 

 horns are obliquely concave distally, almost spoon-like and some- 

 what dilated, very diflPerent from the conical termination of another 

 skull from Texas which I must refer to D. magnicomis, as also 

 from the horns of one of the small species from the Orlando bone- 

 beds. 



This modification of the extremity seems to imply a distinct 

 functional use; very probably, as has been suggested, for the pro- 

 tection of the branchiae. In the earlier amphibians the lateral 

 cornua may be composed either of this element or of the prosqua- 

 mosal (or supratemporal ) ; in the the latter case the otic notch 

 between the two. In reality, the same notch is found in Diplocaulus 

 between the epiotic and the prosquamosal on the lateral aspect of 

 the skull. As regards the homologies of the two elements called 

 here the squamosal and prosquamosal tliere has been, as is well 

 known, much contention. Cope called these bones in Diplocaulus 

 the supramastoid and supratemporal. The more usual nomencla- 

 ture is the squamosal and supratemporal, but indifferently applied. 

 That they agree well in position and relations with the correspond- 

 ing elements of the Microsauria is apparent, and I shall continue 

 to call them, after Baur, the squamosal and prosquamosal until the 

 problem of their homologies is more satisfactorily settled than is 

 at present the case. The squamosal ( SQ ) is a small bone, articu- 



