Mr. T. Attliey on Pteroplax cornuta. 375 



with regard to the third fragment, which may be a part of the 

 first-named. 



These ribs, lying in contact with the skull of Pteroplax, 

 must be taken as having belonged to the same animal. 



The ribs imbedded on a piece of shale cannot, perhaps, be 

 proved to have belonged to Pteroplax ; but they are of the 

 same size, and are in other respects very like those on and 

 under the cranium, and were found in the same part of the 

 mine. 



If this inference be correct, then the vertebrge lying with 

 the ribs on the piece of shale are, there can be little doubt, 

 vertebra of Pteroplax. 



Bones of an extremity. — These are figured on Plate XIII. 

 fig. 3, and are only three in number, small and dislocated from 

 their normal relation, but still very near to each other ; they 

 lie surrounded by many scutes on a slab of shale 8 inches by 

 5i inches. They appear to be the terminal bones of a digit, 

 but whether of an anterior or posterior limb is not easy to de- 

 termine. They diminish in size like digital bones : the biggest 

 is 1 inch long and \ inch wide ; the next is shorter and more 

 slender ; the third or smallest is pointed at the further end ; 

 with this exception the ends of these bones are concave and 

 the sides contracted at the middle. 



Scutes. — On the last-mentioned slab, and on its counterpart 

 measuring bh inches by 4^ inches, are imbedded altogether 

 104 scutes, lying in the same plane, but scattered about with- 

 out any order ; besides these I have only one other scute on a 

 small bit of shale in my collection. 



These scutes vary in size from 1 to | inch in length ; and 

 from ^ inch at the anterior end, which is rounded, they taper 

 to a rather sharp point behind ; their upper surface on the 

 whole is convex and their under surface concave from end to 

 end. On their upper surface is a strong ridge nearer to one 

 margin than the other ; the former is the thicker edge and also 

 the longer, whilst the surface slopes gradually to the other 

 side, which is quite thin. Two of these scutes are represented 

 in PI. XIII. fig. 2. 



It is presumed that the above are the scutes of Pteroplax^ 

 as they are different in form from the scutes of the two other 

 larger Labyrinthodont Amphibia, and are also much smaller 

 and of more delicate make, and we know of no other animal- 

 remains in our coal-field to which they could belong. They 

 are from the same part of the mine as the other remains herein 

 noticed, and bear a certain proportion of size to the crania 

 described. 



The small size of the crania, their form and the smaller 



