220 B. NATURAL HISTORY. 
while the suspensorial type is the most divergent from other Verte- 
brata, and most specialized. Hence the 
successional relation of the orders of 
Reptilia is to be estimated by reference 
to their degree of approximation to 
either of these extremes, as will be con-- 
sidered further on. 
If we seek for that element, in the 
Crocodilia, which fulfils the requisites / 
of the squamosal as above defined, we 
find it on the posterior superior lateral 
angle of the cranium. (See fig. 18, Sq.) 
It sends forwards an anterior process, 
which completes the zygomatic arch 
posteriorly, and with the postfrontal 
(Pf) bone encloses the temporal fossa. 
As its union with the quadratum is on 
the under side of the latter, it is con- 
cealed from view in fig. 18, chiefly by 
the superior prolongation of the quad- 
ratojugal (QJ). 
In the Testudinata, the quadrate be- 
ing removed from the cranial walls, the 
position of the squamosal is more ex- 
terior. (Fig. 10, Sq.) In Chelone, it 
sends an extension upwards to the pa- 
rietal, forming the parieto-quadrate 
arch, which is not observed in most 
other Testudinata. The enclosed space 
is much more expanded than in Croco- 
dilia (fig. 11), where it is in fact reduced 
to a foramen above each supraoccipi- 
tal. 
The position of the squamosal in the 
Pythonomorpha is very similar to that 
seen in the last order, but it is further 
removed from the cranial walls (fig. 19, 
Sq), in consequence of the greater 
length of the suspensorium. 
‘soyore YA ‘cantavso Jo apyoud { uoyyAdord soysepyQ — ‘eT ‘SIT 
In the Lacertilia it is carried far from 
the cranial walls by the increased length of the exoccipital, from 
