562 CARBONIFEROUS LABYRINTHODONT 
Although I worked out this region of the skull with extreme care, 
I was in doubt whether the aperture in question was really a natural 
one, until I cleared away the matrix from the opposite side, and there 
found a foramen of quite a similar character, though distorted by the 
crushing of this part of the skull. 
The premaxillary bones, strong and arched, send back two processes 
from their opposed ends, which run upwards and backwards in the 
middle line (in the manner common in Amphibia) towards the junction 
of the vomers. As the anterior portion of the vomerine plate is 
inclined upwards and forwards, it follows that the most anterior region 
of the palate has 4 somewhat arched roof, as in the Frog. The 
anterior palatine foramina (a), included between the recurrent 
processes of the premawillaries, their dentigerous processes, and the 
vomers, appear to be about 1) inch long by 1 inch wide; but it is 
difficult, from the condition of the fossil, to define their limits with 
exactitude. 
Thirty-seven teeth, or remains of teeth, are visible. Of these, on 
the left side, thirteen are situated in the premaxilla and mavwilla, 
and three on the palatine bone ; while, on the right side, nineteen are 
attached to the premanilla and maxilla, one to the vomer, and one to 
the palatine bone. On the whole, the maxillary teeth decrease in size 
from before backwards, but not very regularly. The first tooth on the 
left side was 1°7 inch long when entire, by about half an inch thick at 
the base. The second immediately follows it, and is somewhat larger. 
The third, of about the same size as the second, is separated from the 
latter and from the fourth, by spaces about three-quarters of an inch 
wide. The fourth tooth, broken short off, must have been a very large 
one, being not less than three-fourths of an inch in diameter at the base. 
It is separated by a deepish fossa, 0'7 inch wide, from the succeeding 
tooth. This, the fifth, is close to the sixth, and both are small, the base 
of neither attaining more than o°3 inch in diameter. The seventh and 
eighth teeth, rather large, are situated at tolerably equal intervals from 
one another, and from their predecessors and successors, in the 
interspace of about 2 inches which separates the sixth from the ninth 
tooth. There are marked fossz, as if for the reception of the points 
of mandibular teeth, between them. The bases of the ninth and tenth 
teeth, close together, occupy 0'7 inch. They are separated by a space 
of about half an inch from the eleventh tooth, and this by a somewhat 
smaller interval from the twelfth, which is close to the thirteenth. The 
bases of these last-mentioned teeth do not exceed o'4 inch in diameter. 
The last tooth is nearly on a level with the anterior margin of the 
palato-temporal foramen. There is a fossa of nearly the same size 
