194 THE COAL MEASURES AMPHIBIA OF NORTH AMERICA. 



Dendrerpeton oweni Dawson. 



DAWSON, Quart. Jour. Geol. Soc. London, xvm, p. 460. 



DAWSON, Air-breathers of the Coal Period, p. 32, 1863. 



DAWSON, Acadian Geology, 3d ed., p. 368. 



DAWSON, Phil. Trans. Roy. Soc. London, pt. n, p. 643, pi. 44, figs. 131, 138, 139, 1882. 



A smaller species than the preceding. The form (plate 13) is fully described by 

 Dawson (Air-breathers of the Coal Period, p. 32, pi. iv, 1863) as follows: 



"Among the reptilian remains found in erect trees at the South Joggins, there have 

 occurred several portions of skeletons which, from their sculptural cranial bones, plicated 

 teeth, and the forms of their scales and limb-bones, I have referred to the genus Dendrer- 

 peton, but to individuals of much smaller size than the full-grown specimens of D. acad- 

 ianum. It did not occur to me to suppose that these were specifically distinct from the 

 larger individuals, until I observed that bones of this kind, contained in the collections sent 

 by me to the Geological Society, or represented in the figures drawn to illustrate one of my 

 papers, were referred by Professor Owen, in his notes on these specimens and figures, in the 

 Journal of the Geological Society, to the genus Hylonomus; which is quite distinct from 

 Dendrerpeton, as will be explained in sequel. 



' ' I was thus induced to reexamine all the specimens in my collection and the result has 

 been to establish a strong probability that there is in reality a second species of Dendrer- 

 peton, smaller than D. acadianum, and differing from it in several points. This species I 

 propose to name D. oweni. It differs from D. acadianum in the following particulars: (i) 

 its much smaller size; (2) its long and hooked teeth (it will be seen that these teeth differ 

 very markedly in their proportions and form from those of the larger species) ; (3) the greater 

 plication of the ivory in the intermaxillary teeth (in D. acadianum these teeth are, on the 

 outside, simple almost to the base, and plicated on the inner side, while in this species they 

 are plicated all around like the inner maxillary teeth) ; (4) the form of the skull, which has 

 the orbits larger in proportion, and is also shorter and broader. On the other hand, when 

 we have described the species Hylonomus, it will be seen that this animal, except in size, 

 differs from them quite as widely as does D. acadianum. 



' The distinctness of D. oweni is further confirmed by the fact that I possess small 

 jaw-bones of Dendrerpeton, about the size of those of this species, but having the teeth 

 similar in form to those of the larger species ; these I suppose to have belonged to young 

 individuals. 



"On examining the figures (208, pi. iv) it will be seen that the bones of the skull were 

 corrugated as in the large Dendrerpeton, but with a smaller pattern. The forms of the jaw- 

 bones also, and of the vertebrae, ribs, scapular bone, bones of the limbs, and bony scales, are 

 very similar, and indicate that in general form this creature was not far removed from its 

 larger relative. The bones of the foot especially deserve attention. This is the most per- 

 fect foot of Dendrerpeton hitherto found; and I have enlarged it in the figure (208) in order 

 more distinctly to show its parts. It presents three long toes with traces of a smaller one at 

 each side, so that there were probably five in all. If these toes be compared with the foot- 

 prints on the slab discovered by Dr. Harding, it will be seen that they very closely corre- 

 spond, though the toes of the present species are much smaller. The footprints are precisely 

 those which we may suppose an animal of the size of Dendrerpeton acadianum would have 

 made if, as the bones found render in every way probable, this larger species had a foot 

 similar to that of D. owcni. I suppose, for this reason, that these footprints are really those 

 of Dendrerpeton acadianum and that this species continued to exist from the time of the 

 lower Coal Measures to the period when those higher beds of the series, in which its bones 

 are found at the Joggins, were deposited. 



' The present species must have lived in the same places with its larger relative, but 

 may have differed somewhat in its habits. Its longer and sharper teeth may have been 



