856 The American Naturalist. [September, 
thors who think that the paroccipital of the Squamata, Crocodilia, etc., 
is fused with, and undistinguishable, in the adult skull, from the exoc- 
cipital. As proof that this is the case, he cites the opinion of various 
authors, and especially that of Hallmann, who, he alleges, demonstrated 
this to be the fact in 1837. On this essential point it may be remarked, 
first, that most of the authors cited have simply supposed this to be 
the case without making any attempt to demonstrate it. Second, 
although I have repeatedly examined crania of lizards from the 
first appearance of ossification, I have never observed a distinct 
center in the position of the paroccipital of tortoises and which Hall- 
mann and others regard as the representative of that bone; nor have 
I observed it in the Crocodilia. W. H. Parker has not seen it, nor 
does Baur say he has done so. After having announced his dis- 
covery of it in Sphenodon, he afterwards changed his mind and con- 
cluded that he had been misled by appearances. Until the presence of 
such an element in the Squamata is demonstrated, I must continue to 
regard the element called by Baur in that order, the squamosal, as the 
paroccipital. In the Mosasauroids the element has more nearly the 
position of the paroccipital of tortoises than in any other of the Squa- 
mata. I may say that I have not been able to see Hallmann’s mem- 
oir, and that [ am entirely open to conviction when the evidence shall 
be produced, though I suspect that it will not be forthcoming. 
In stating his disagreement with my conclusion on this point, the au- 
thor does not make it clear that he has come to agree with me in two 
points on which we formerly differed. Thus he now agrees with my 
view of 1871, that the single postorbital bar of the Lacertilia is homol- 
ogous with the superior bar of Sphenodon, and not the inferior, as he 
has recently maintained, though he at one time agreed with me. He 
also agrees that the suspensorium of the quadrate of the Ophidia is the 
paroccipital (squamosal Baur), and not the supratemporal (prosqua- 
mosal Baur); an opinion in which I have been alone hitherto. 
If the element which I have identified with the paroccipital in the 
Squamata, is not that element, it is not thereby proven that it is iden- 
tical with the squamosal of the Mammalia. Moreover it cannot be ho- 
mologous with the element in the Ichthyosauria, Cotylosauria and 
Stegocephalia with which Baur identifies it, since it is a brain-case 
bone, while the latter is a temporal roof-bone,a fundamental differ- 
ence. For this reason I have called the latter the supramastoid. (See 
my paper on the Transactions of the American Philosophical Society, 
1892, p. 11). : 
