38 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



extending from the exoccipital forwards and a little outwards to the 

 postfrontal, where it bends more directly outwards and downwards 

 behind the orbits : these grooves probably lodged large mucous canals. 

 Portions of small, conical, pointed, subequal teeth extend in a single 

 series along the alveolar border of the upper jaw (fig. 2, 21), from 

 the muzzle, along the lateral borders of the fossil, to two-thirds of an 

 inch behind the orbits. At the bases of some of these teeth may 

 be discerned indentations converging from the periphery towards 

 the centre of the dentine. 



The entire orbits, closed below by a backward extension of the 

 superior maxillary (21), and the connexion of this bone by a malar 

 (26) and squamosal (27) with the mastoid (s) and tympanic (23), 

 forming a complete zygoma, prove that the fossil did not belong 

 to the class of fishes : whilst the strong points of resemblance which 

 the skull presented to the Lahyrinthodonts — ^in its broad and very 

 depressed figure (especially the great breadth of the occiput), in its 

 external sculpturing (especially the number and position of the mu- 

 cous grooves), in the form and position of the orbits, and in the cha- 

 racters of the teeth — led me to investigate the structure of the deeper 

 part of the occiput which was concealed in the matrix, for the more 

 decisive character which that part of the cranium affords of the ba- 

 trachian affinities of the singular reptiles to which the Mangali skull 

 seemed by its more obvious characters to be most closely allied. 



I was gratified by finding that the occipital bone (which like the 

 rest of the skull was distinguished from the red matrix by its yellow 

 colour) terminated posteriorly in two well-defined subdepressed con- 

 vex condyles, 2, 2, not so close together as in the great Labyrinthodon 

 saletmandro'ides {Mastodonsaurus of Jaeger), but separated as in the 

 Trematosaurus of Burmeisterf . A part of the broad atlas {a) was 

 found in connexion with these condyles. 



The superoccipital region is formed by a pair of bones, 3, 3, each 

 with a slightly prominent centre at the angle between the horizontal 

 and backwardly-sloping part of the occiput : they may represent a 

 divided superoccipital bone, but I cannot trace a suture separating 

 them from the exoccipitals supporting the condyles, where it is repre- 

 sented by Burmeister in the Trematosaurus. 



External to these is a large bone with a well-marked prominent 

 centre, from which the grooves of the outer surface radiate : on the 

 left side, a part of the tympanic remains in connexion with this bone, 

 which I regard as the mastoid, s, which bone occupies a similar posi- 

 tion in the Lahyrinthodonts. The parietal bones, 7, 7, continue the 

 cranial walls in advance of the superoccipitals, and show a small oval 

 vacuity in their median suture — the "foramen parietale," as in the 

 Trematosaurus : the foramen is situated near the hinder part of the 

 suture : an accessory parietal, 7*, extends outwards from the hinder 

 half of the main body of the bone on each side, to the angle between 

 the superoccipital and mastoid. Traces of a suture seem to show 

 this to be a dismemberment of the parietal : it occupies the place of 

 the bone marked n, and called "os temporale squamosum," in the 

 t 'Die Labyrinthodonten,' 4to, 1849, part i. pi. 1. 



