ET2 ON THE STAGONOLEPIS ROBERTSONI AND THE 
faces, but there is no evidence that they possessed any definite cutting 
edge. The manner in which the teeth are crushed and cracked to- 
wards their alveolar ends indicates the existence of a large pulp- 
cavity, bounded by comparatively thin walls. 
The alveoli are quite distinct from one another. The bony sub- 
stance of the jaw has left such an impression as leads to the belief 
that it must have had a coarsely fibrous structure, more like that of 
a fish than that of a reptile. There is also a remarkable irregularity 
and want of parallelism about the disposition of the teeth, the fifth 
being greatly inclined backwards, and the second having a similar, 
though less marked, obliquity. 
There is no positive proof that this fragment of a jaw belonged 
to Stagonolepis ; but, as I have already stated, no vertebrate remains 
save those of this reptile have hitherto been found in the Findrassie 
quarry, whence the specimen was obtained, and the external charac- 
ters and mode of implantation of the teeth are wholly unlike those 
of any of the large, probably piscine, teeth (of Dendrodus, e.g.) which 
have been discovered in the neighbouring beds of the Old Red 
Sandstone. (See the final Note, p. 117.) 
If this jaw belonged to the same animal as that to which even the 
largest of the vertebree which have been discovered belonged, the size 
of the teeth is remarkable, for the longest is considerably more than 
twice as long as the centrum of such a vertebra. On the other hand 
it must be recollected that the teeth of some of the ancient Ze/eo- 
sauria are extremely long in proportion to the jaw, and in other 
respects present resemblances to those contained in the fragment just 
described ; while it is also possible that this fossil may have formed 
a part of an individual larger than any of those whose vertebra have 
as yet come to light. «As the evidence stands at present, I see no. 
reason to doubt that the jaw belonged to Szagonoleprs. 
Assuming that S¢agonolepis had the same general proportions as 
a Crocodile—as, from the characters of the jaw, femur, and caudal 
vertebra, we have every reason to believe was the case—the largest 
remains I have met with, excluding the jaw just mentioned, indicate 
an animal about eight feet long. (See Note, p. 171). 
Affinities of the Stagonolepis—With regard to the affinities of the 
Reptile whose leading structural peculiarities have been detailed in 
the foregoing pages, I think it is clear that S/agonolepis is, in the 
main, a Crocodilian Reptile. Its dermal armour, its sacrum, its 
scapula, are eminently crocodilian ; its femur and dorsal and caudal 
vertebra are also crocodilian, though presenting small aberrations 
from the pure type. The teeth, though more divergent, are croco- 
