1862.] HUXLEY CARBONIFEROUS LABYRINTHODONT. 57 



but almost the whole of this surface was obscured by a thick coat 

 of the matrix, in which were partially imbedded many of the 

 long and pointed crowns of the teeth. These had been broken off, 

 and lay not very distant from their stumps, with their points all 

 directed inwards, towards the middle line of the palate. Their 

 arrangement was just such as might have been expected if the axes 

 of the teeth had naturally been turned somewhat inwards, and the 

 vertical crush of the superincumbent strata, after the fossilization 

 of the skull, had consequently caused them all to fall inwards as 

 they broke. The same pressure has produced a slight asymmetry of 

 the whole skull. 



From the proportional size and structural features of the teeth, and 

 from the general contour of the skull, I concluded this to be a new 

 genus of Labyrinthodonts ; but in order to make sure of the point, I 

 proceeded to develope the fossil, from the hard matrix in which it was 

 imbedded, with much care ; removing some of the teeth and, on one 

 side, even a portion of the bony palate, in order to obtain a view of 

 those parts, such as the orbits and posterior nares, which would enable 

 me to decide the question. 



The skull, as it now appears (fig. 1), presents almost the whole 

 of its palatine or inferior surface to view, with the exception of the 

 right temporal region. Its greatest length, measured along a me- 

 dian line drawn from the middle of the premaxillary region to a level 

 with the posterior and external points of its prolonged and broad 

 temporal prolongations, is 15 inches. Its greatest width, obtained 

 by doubling the distance from the left posterior and outer margin to 

 the middle line, is 12 inches. Opposite the great vomerine tusks (d), 

 the skull measures 5*3 inches in width. It diminishes slightly from 

 this point to the rounded snout, and gradually increases in breadth 

 posteriorly to the level of the supratemporal foramina (c), where it 

 measures about 10 inches in width. Beyond this point it widens 

 suddenly by about half an inch on each side, and the lateral contours 

 continue to diverge from hence to a point about 2| inches distant 

 from the hinder extremity of the temporal prolongations of the 

 skull. The external contour of the temporal prolongation now 

 becomes rounded off, and sweeps evenly inwards, until it meets the 

 internal contour, which appears to be nearly straight. The epiotic 

 processes are not visible. 



In the middle line of the base of the skull, extending as far back- 

 ward as the level of the posterior part of the supratemporal fora- 

 men, is the well-ossified basisphenoid, 1*7 inch broad, and slightly 

 excavated posteriorly. The basisphenoid narrows anteriorly, so that, 

 at 1*4 inch from its posterior extremity, it is not more than 0*9 

 inch wide ; beyond this point it suddenly widens to form the 

 lateral processes, like those commonly exhibited by the basisphenoid 

 of fishes, and then rapidly tapers forward, having, at 2-8 inches 

 from its hinder extremity, a diameter of not more than 0*25 inch, 

 and continuing straight and style-like as far as it can be traced, 

 which is to a distance of about 6 inches from its hinder extremity. 



The limits of the vomers cannot be accurately defined ; but they 



