1858.] HUXLEY — STAGONOLEPIS. 455 



rior faces, but there is no evidence that they possessed any definite 

 cutting edge. The manner in which the teeth are crushed and 

 cracked towards 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 E^ed 

 Sandstone. (See the final Note, p. 459.) 



If this jaw belonged to the same animal as that to which even 

 the largest of the vertebrae 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 Teleosauria 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 vertebrae have as yet come to light. As the evidence stands 

 at present, I see no reason to doubt that the jaw belonged to Sta- 

 gonolepis. 



Assuming that Stagonolepis had the same general proportions as 

 a crocodile — as, from the characters of the jaw, femur, and caudal 

 vertebrae, 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. 459.) 



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 Stagonolepis is, in the 

 main, a Crocodilian Eeptile. Its dermal armour, its sacrum, its 

 scapulae, are eminently crocodilian ; its femur and dorsal) and caudal 

 vertebrae are also crocodilian, though presenting small aberrations 

 from the pure type. The teeth, though more divergent, are croco- 

 dilian in their mode of implantation and some other respects. The 

 coracoid,on the other hand, is lacertiHan or dinosaurian*; and finally, 

 if one may safely judge from the few remains which have hitherto 

 presented themselves, the bones of the feet were neither crocodilian 

 nor dinosaurian nor lacertilian. 



* See the Note at the end of the paper. 



