532 ON CARBONIFEROUS LABYRINTHODONTS 
posterior margin of the skull, and then passes backwards into the 
lateral boundary of the epiotic bone. The posterior contour of the 
skull consequently presents a deep notch between the epiotic bone 
and the plate in question. The epiotic bone, small and pointed 
posteriorly, is wedged in between the supraoccipital element, the 
parietal, and the squamosal. 
The description here given refers chiefly to the right (proper) 
half of the skull. The left half is broken away, so as to leave only 
the left supraoccipital, the left parietal, and part of the left frontal 
and postfrontal. The complete preservation of the latter bone for- 
tunately enables one to form an accurate judgment of the minimum 
width of the interobital space. 
The structure of the cranial fragment which has been described 
proves it, without doubt, to belong to a Labyrinthodont Amphibian, 
and affords sufficient evidence of the character of the whole skull. 
The straightness of what remains of the external edge renders it 
probable that the skull was elongated, like that of Archegosaurus ; 
and on completing the left side of the posterior part of the skull by 
the aid of the right side, and restoring the general contour on the 
basis of Archegosaurus, we get a diagram of the whole skull which 
is probably not very far removed from the truth. 
Posteriorly the skull had a width of 10} inches; and if the snout 
were even less acute than that of Archegosaurus, its total length 
would be about 14 inches. The largest Archegosaurus skull known 
does not exceed 12 inches in length. 
From the skull of Archegosaurus, and from that of all other 
Labyrinthodonts at present known, the present specimen is distin- 
guished by the proportional size, backward position, form and 
very oblique disposition of the long axis of the orbits. And as the 
orbits of species of known genera of Labyrinthodonts do not differ 
from one another in any essential respect, I conceive this character 
to be of generic importance; and I propose the name of Loxomma 
for the new genus thus characterised. The species may be termed 
Loxomma Allmannt, after the eminent Professor of Natural History 
in the University of Edinburgh, who aided me so essentially in dis- 
covering it. 
The skull, however, was not the first relic of this interesting 
Amphibian which came to light. What, in fact, originally led me to 
divine the existence of a large new Labyrinthodont in the Scotch 
coal-field, was the discovery of a rhomboidal plate of bone so ex- 
tremely similar to the middle sternal plate of a Labyrinthodont as 
at once to awaken suspicion. Subsequently I found another speci- 
