THYNG: SQUAMOSAL BONE. 
405 
Lortet’s ‘apophyse’ (St.) forms the external boundary of the post¬ 
temporal fossa and articulates anteriorly with the parietal (Pa.), 
(but from Lortet’s figure is clearly distinct from it) and externally with 
the postorbital (or postfrontal, Po.) and with the posteriorly placed 
squamosal (Sq., temporal of Lortet). In its posterior extension it 
bends medially over the supra-occipital (posterior processes of the 
parietal of Baur, ’94) nearly reaching its fellow of the opposite side 
(a condition possibly due to dislocation of parts). It can have no 
relation to the external surface of the quadrate, neither does it artic¬ 
ulate with the postorbital (Po.) in a manner characteristic of the 
squamosal in the Stegocephala and Cotylosauria, but it agrees with the 
supratemporal in position and relations and, as Boulenger has sug¬ 
gested, should be called by that name. 
Lateral to the supratemporal (fig. J, St.) is a second bone (Sq.), the 
temporal of Lortet, prosquamosal of Baur (’94) and Osborn (:03) 
which, according to Lortet, articulates with the quadrate (“s’artic- 
ulant en arriere avec un os carre”) but it is not certain what he 
regards as the quadrate, and there is nothing in his figure which I can 
interpret as such. In front, it articulates with the postorbital while 
Fig. K. — Restoration of the skull of the Pelycosauria, from above, after Baur 
and Case. F., frontal; J., jugal; L., lachrymal; Mx., maxillary; N., 
nasal; Pa., parietal; Pf., postfrontal; Pmx., premaxillary; Po., post¬ 
orbital; Prf., prefrontal; Qj., quadratojugal; Sq., squamosal; St., supra¬ 
temporal. 
the parts with which it is connected laterally are not so easy to 
determine. Comparison with the Stegocephalian skull (e. g., Bran- 
chiosaurus, fig. C) would seem to indicate that the element lat¬ 
eral to the left temporal is the jugal (J.) while on the posterior 
lateral margin of this is the quadratojugal. These facts, and espe¬ 
cially the relation to the quadrate, if Lortet’s account be accepted, 
demonstrate this element to be the squamosal. 
In the Pelycosauria (figs. Iv and L) there occurs not only a post- 
