562 PROF. OWEN ON THE ENDOTHIODONT REPTILIA. 
pl. lx. fig. 2), remains to be determined by more perfect specimens of 
findothiodon. 
The hind portion of the broken specimen of Endothiodon wniseries 
includes the fore part of the temporal fossa (fig. 2,¢), The rhinen- 
cephalic canal (fig. 3, rh.), 6 lines in width, 3 lines in height. is 
exposed at the fracture in advance of the prosencephalic cavity ; its 
fractured roof includes a vertical thickness of more than an inch of 
solid bone. Density and massiveness are eminent characteristics 
of the skull of the present Triassic reptile. The upper surface 
anterior to the temporal fossee is boldly and irregularly sculptured. 
The conyex nasal process of the premaxillary (fig. 4, 22’), with the 
anterior ends of the frontals (11) interwedged, is divided by large 
and deep channels from the elongate similarly convex and rugous 
nasals, 15, and prefrontals, 14, which augment the breadth of the 
eranio-facial platform. The prefrontal, 14, develops a roughened 
boss at the fore part of the orbit, anterior to which boss opens a 
large pseudo-narial foramen (fig. 2, a), the homologue of that which, 
in Veleosaurus*, also coexists with a true external nostril. 
The postfrontal, 12, develops a similar boss, and the lower inter- 
mediate part of the upper border of the orbit may be contributed by 
either a superorbital bone or by an outward extension of the frontal, 
Hye 
The numerous fissures and irregular indentations over the tuberous 
and wrinkled upper surface of the skull render the determination of 
sutures between the frontals and superorbitals more or less ambi- 
guous; but the example of Oudenodon Greyi (op. cit. pl. bxii. 
fig. 2, 11), in which the mid frontals are plainly divided by a suture 
from a narrow superorbital bone, weighs towards the belief of a 
similar ossicle, as marked at 11’ in fig. 4, Pl. XXVII., completing the 
upper rim of the orbit, on a lower level than the pre-and postfrontals, 
in Endothiodon wniseries. 
I come now to the question of the additional light thrown by the 
skull of this species on the affinities of the genus in the Reptilian © 
class. Amongst the cranial characters of the order Anomodontia are 
the following :—Premaxillaries confiuent, forming a single edentu- 
lous beak-shaped bone, sending upward and backward a ‘ nasal pro- 
cess,’ and forming below the roof of an anterior palatal vault, from 
which roof a process is continued backward to the vomer.’ ‘The 
nasal bones more or less divided by interposition of the nasal process 
on the premaxillary’f. Vomer consisting of a pair of vertical 
lamelle contributing little to the bony roof of the mouth, dividing 
the narial passages at some distance from the wide and single 
palato-naris or posterior nostril.” 
In these characters Hndothiodon agrees with the Anomodontia and, 
* ‘Hist. of Brit. Foss. Reptiles,’ part. iii. (Crocodilia, pl. i. fig. 2, a). 
+ The sutures demonstrating this character are well shown in the skull of 
Piychognathus declivis (Foss, Rept. 8. Afr. pl. xlv. figs. 2, 15, & 22). The divided 
condition of the nasals and their relation to the outer nostrils repeat, in Birds, the 
structure here shown in Anomodonts. See Dinornis robustus, ‘ Wingless Birds 
of New Zealand,’ pl. lxiy. figs, 2, 15, 22; and Aptornis, pl. lxxxiii. figs, 15 & 22. 
