418 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
In the skulls of the Theriodontia, the Anomodontia, and the Saurop- 
terygia the squamosal is the only bone which invests the temporal 
region. 
The squamosal of the most primitive reptiles, the Cotylosauria, 
shows practically the same relations as that of the Stegocephala. 
In the Iehthyosauria the squamosal covers the dorsal external sur¬ 
face of the quadrate, and articulates anteriorly with the postorbital, 
laterally with the quadratojugal, and dorsally with the postfrontal 
and supratemporal. 
Comparison of the skulls of Sauranodon, the Pelycosauria, Steno- 
metopon, Palaeohatteria, and Sphenodon leads to the conclusion that 
in the phylogenetic development of the last genus the supratemporal 
has been lost, and the bone which remains is the squamosal, its con¬ 
nection with the parietal being correlated with the disappearance of 
the supratemporal. 
In Sceloporus the squamosal consists of two parts, an anterior proc¬ 
ess which articulates with the postorbital and jugal, and a posterior 
portion which develops in membrane upon the otic capsule and over¬ 
laps the dorsal >extension of the quadrate. The supratemporal has 
undergone marked reduction which seems true of the Lacertilia as a 
class. In the fossil forms, Platycarpus and Liodon, the relations of 
the squamosal are practically the same as in the Lacertilia. 
The single bone existing in the temporal region of the Ophidian 
skull has the same development as the supratemporal of the Lacertilia 
and cannot be called the squamosal. 
In the Crocodilia we find a bone which develops in membrane upon 
the otic capsule and overlaps the dorsal extension of the quadrate, 
eventually occupying the postero-lateral superior angle of the skull. 
This is evidently the squamosal. The supratemporal is lacking, 
at least no embryological evidence has yet been produced as to its 
existence. 
In the Dinosaurian skull it seems very probable that the supra¬ 
temporal is lacking and the bone which adjoins the parietal and ex¬ 
tends more or less ventrally alongside the quadrate, is the squamosal. 
The term ‘paraquadrate’ introduced by Gaupp, and since adopted 
by several authors, is unnecessary, since (if we adopt the incus = 
quadrate homology), that bone of the Urodelan skull which Gaupp 
and his followers call the paraquadrate, agrees perfectly with the 
mammalian squamosal, and should be so named. Moreover, Owen’s 
