62 Messrs. Hancock & Atthey on a new Labyrinthodont 
The folded margin of the cranium exhibits in front a longi- 
tudinal depression, which there can be little doubt indicates 
the position of the orbit; indeed at one point the inner orbital 
margin can be traced. A similar depression is observable in 
the other specimen, at the right side. The only other feature 
worthy of notice in our second specimen is the pterygoid ; that 
on the lett side is pretty well preserved, and shows no varia- 
tion of character, except that the surface is minutely striated 
in a longitudinal direction. 
For three or four years past, Mr. Atthey has had in his 
possession a mandible belonging to this new Labyrinthodont ; 
and, though always believing it to be distinct from that of any 
known species, we have kept it back till now, not feeling our- 
selves justified in encumbering the nomenclature with terms 
signifying so little and, in a scientific point of view; almost 
valueless. We are now, however, in a position to associate it 
with a cranium possessing important and interesting features. 
There can be no doubt that this mandible is really that of 
Batrachiderpeton. The surface-character of the bone, its size, 
and the character, form, and size of the teeth all go to prove 
is. 
This mandible is perfect in front, where it is obtusely 
pointed; behind it is imperfect, a considerable portion evi- 
dently having been removed. The outer surface is exposed, 
and is seen to be covered with a few coarse, irregular, longi- 
tudinal ridges, having much the character of those on the 
cranium ; and in front there are a few reticulated ridges, quite 
similar to those on the premaxille. It is an inch long and a 
quarter of an inch broad at the widest part; the margins are 
nearly parallel, the jaw narrowing only very slightly forwards; 
the Ms border is thick and almost straight, there being à 
slight depression near the centre, dividing the teeth into two 
groups. In all, there are fifteen teeth; they are closely 
arranged, stout, a little incurved, rather obtusely pointed, and 
have the tips finely striated and slightly compressed in the 
direction of the length of the jaw—agreeing in these pecu- 
liarities, as in all the other characters, with the premaxil 
teeth ey are confined to the anterior portion of the man- 
dible, there apparently having been none in the posterior part. 
The range of the teeth will therefore correspond very well to 
those of the præmaxilla. They are the sixteenth of an inch in 
length, being of the same size as those of the preemaxilla. 
it is impossible to contemplate the structure of the roof of 
the mouth of this curious Labyrinthodont without being re- 
minded of the arrangement of the parts in that of Siren, Pro- 
teus, and Axolotl. The well-armed vomer in particular is 
