THYNG: SQUAMOSAL BONE. 
413 
mastoid and in this he was followed by Stannius (’46), Owen (’66-’68), 
and others. Hallmann, however, homologized it with the mammalian 
squamosal (squama temporalis) and since his day it has been generally 
known as the squamosal. 
According to Parker, whose figures I have reproduced, this element 
develops in Crocodilus palustris (fig. Q) upon the otic capsule, and 
here, as in the alligator (fig. R) extends down upon the dorsal external 
surface (otic process) of the quadrate. Parker gives no evidence, 
in either text or figures, as to whether this is the condition in the young 
Fig. R. — Side view of the skull of Alligator mississippensis (large embryo), 
after Parker. «/., jugal; Mx„ maxillary; Pa., parietal; Po., postorbital; 
Qj., quadratojugal; Qu., quadrate; Sq., squamosal. 
or whether it is reached in the later stages alone. If the latter, it only 
parallels the condition in Sphenodon. From these early facts as well 
as its position lateral to the supratemporal fossa and its articulation 
with the postorbital, I can but agree with the majority in regarding 
it as the squamosal. 
The lower arcade is formed of two bones, an anterior jugal (J.) 
which articulates in front with the maxillary and is produced behind 
to meet the second element ( Qj .), which was called the temporal 
ecailleux by Cuvier, the quadratojugal by Hallmann, the squamosal 
by Owen (’66-’68), and the paraquadrate by Gaupp. Gaupp came to 
this conclusion by a comparison with Sphenodon when he regarded 
