NATURAL HISTORY SOCIETY OF GLASGOW. 175 



ganoin still remains, while a scale of Megalichthjs is impacted in 

 the anterior angle. Fig. 3 is a view of the inner surface of a jaw, 

 of which the hinder part is lost as in Fig. 1; but of the missing 

 portion the cast is still perfect, and shows a glossy surface, the 

 counterpart of the smooth ganoin of Megalichthys. The conical 

 teeth are not so small in proportion to the size of the jaw as would 

 appear from Fig. 1. The specimen, Fig. 3, shows them to be of 

 ordinary megalichthyc type. 



So far there is no reason for believing that the bone in question 

 is other than the jaw of MegaUchthys. But Prof. Owen puts 

 forward certain positive characters as indicating labyrinthodont 

 nature. Thus he considers the maxillary to be of " greatest height 

 al^out one fourth from maxilla-premaxillary-suture; thence it 

 diminishes in height, at first rapidly, afterwards gradually, termi- 

 nating in a point far behind the orbit, as in the Labyrinthodont 

 Making abstraction of these two bones, mx and pmx, there 

 remains an area made up of " the portions of the bones that seem 

 best to answer to the lachrymal and malar in Archegosaurus and 

 Labyri7ithodo7i" and " the portions of the bones which best corre- 

 spond with the post-frontals and squamosals in the above- 

 mentioned reptiles." Of the six bones here mentioned, I can 

 recognise only one — tlie maxillary; and I unhesitatingly assert 

 that it alone makes up tlie whole of the fossil, and that it is, 

 after all, incomplete in the fossil so circumstantially described. 

 There is no good reason for inferring the fusion of so many 

 parts, since the Leeds specimen of MegaUchthys furnishes evi- 

 dence of a similar single maxilla, and in the Hunteriau 

 Museum there is a specimen in which this bone is seen in place; 

 while, on another slab, we have the isolated bones scattered 

 amidst a great mass of scales belonging to that genus. In the 

 former, as well as in the Leeds specimen, it appears that the orbit 

 lay entirely anterior to the position of Owen's lachrymal; that it 

 was bounded inferiorly and posteriorly by more than one plate, 

 forming a suborbital chain, and that to the margin, named by 

 Owen malar, was ajjplied a supra-temporal bone (or bones) as in 

 Polypterus. The ascending process,* near the anterior extremity, 

 passed upwards and inwards, to be. attached to the pre-frontal, 



* Is this process the "left maxillary," said by Owen to lie across the speci- 

 men ? My notes written before reading the paper cited, do not suggest the 

 presence of two specimens. 



