276 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [DeC. 14, 



the bones of a third are contained in a specimen which I have sent 

 with this paper, for presentation to the museum of the Society. 



A second species is represented by scattered bones belonging to 

 two individuals. In general form and structure it must have resem- 

 bled that above described, but it was twice as large, and its teeth are 

 much more numerous (about 80 in each jaw), and they are flattened 

 and expanded toward their summits (fig. 19). It is also possible 

 that there was a second series implanted on the palate or pharynx, 

 as I have found a few teeth of the form represented in fig. 22, 

 cylindrical, with blunt striated summits. These do not resemble 

 any of the teeth of Dendrerpeton, and are more likely to have be- 

 longed to this than to either of the other species of Hylonomus. 

 There is also a bone which seems to be a sphenoid, having on its 

 anterior part a number of conical tubercles that seem to have sup- 

 ported slender teeth. A foot of one individual is well preserved, and 

 with some other characteristic bones is represented in fig. 1, PI. III.* 

 A magnified view of one of the toes is given in fig. 23. The dermal 

 scales of this species are similar to those of that last described, but 

 are a little larger (figs. 20, 21). I propose for this species the name 

 of Hylonomus aciedentatus. 



A third species, much smaller than either of the former, is repre- 

 sented by bones belonging to at least two individuals. . Its teeth 

 number about 22 in the lower jaw, alternately large and small, 

 conical but obtuse (fig. 24). Its vertebrae are elongated, and the 



Figs. 24-26. — Hylonomus Wymani from the Coal-measures of 

 Nova Scotia. 

 Fig. 24. Fig. 25. Fig. 26. 



Fig. 24. Teeth, magn. 15 diam. Figs. 25, 26. Scales. The nat. size is shown 

 by the vertical line. 



conical cavities at their ends coalesce in the middle of each vertebra, 

 the centrum having thus been cartilaginous in its interior. In one 

 series of these vertebrae, there are as many as 26 joints. Only 

 traces of ribs are seen ; they seem to have been long, but very slender. 

 The feet of one individual are well preserved, and have four toes. 

 Its scales are like those of the other species, but very small and thin 

 (figs. 25, 26). The small vertebrae found by Prof. Wyman in the 

 contents of the former reptiliferous tree, and described in the paper 

 above cited, must have belonged to this species. For this reason I 

 propose for it the name of Hylonomus Wymani. I hope ere long to 

 be able to place the whole collection in the hands of that able com- 

 parative anatomist, that the farther details of their structure and 

 affinities may be more fully worked out. 



* Not engraved. 



