410 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
It may be noted that Williston has apparently fallen into error when 
he says (: 04, p. 188) that in Sphenodon “the prosquamosal has utterly 
disappeared even in the embryo, according to Howes and Swinner- 
ton.” These authors call the prosquamosal of Williston the squamo¬ 
sal, his squamosal the supratemporal, and they nowhere say that it is 
the lateral of these two elements (Williston’s prosquamosal) which 
has disappeared but incline strongly to the view that it is the other 
element which has been lost. 
Squamata .— The Squamata, including the suborders Lacertilia, 
Dolichosauria, Pythonomorpha, and Ophidia, are generally supposed 
to have been derived from a Rhynchocephalian ancestor. 
The temporal region of the skull in the Lacertilia has been fre¬ 
quently studied and very different views of the homologies of the ele¬ 
ments have been advanced. I have studied the development of the 
bones in the skull of Sceloporus and find that in their relations they 
agree fairly well with the account given by Gaupp (’94) for Lacerta 
agilis, although we differ greatly in our interpretations. In figure 5 
(pi. 41) is represented the temporal region of an embryo of Sceloporus 
in which the centers of ossification have just appeared. Lateral and 
ventral to the parietal (Pa.) are two bones. The more dorsal (St.) 
develops as a mere rod upon the otic capsule above the dorsal margin 
of the quadrate (Qu.) and extends from the parotic process of the ex- 
occipital forward to the posterior process of the parietal with which 
it is closely associated from its first appearance. Further, it lies dor¬ 
sal to an element which I shall soon show to be the squamosal. Hence 
in all its relations it is clearly the supratemporal. It has been called 
the mastoid (Cuvier, Stannius, ’46, Owen), squama temporalis (Hall- 
mann, Stannius, ’56), squamosal (Gegenbaur, Baur, ’91 and ’94, 
Wiedersheim, ’93, Gaupp, Gadow, Williston, and others), the opis- 
thotic (Cope, ’71), the paroccipital (Cope, ’72), and the supratemporal 
(Parker and Bettany, Baur, Hoffmann, Siebenrock, and Woodward). 
The lower or more lateral element has been called the temporal 
ecailleux (Cuvier), quadratojugal (Hallmann, Stannius, Holland, 
Gegenbaur, Wiedersheim, Baur, ’89, and others), the supratem¬ 
poral (Cope, ’92, and Gadow), squamosal (Owen, Huxley, Parker 
and Bettany, Cope, *71, Baur, ’87, Siebenrock, and Woodward), the 
paraquadrate (Gaupp), and the prosquamosal (Baur, ’94, and Willis¬ 
ton). In the stage of figure 5 (pi. 41) it consists of an anterior por¬ 
tion, which articulates with the postorbital (Po.) and is thus indirectly 
