376 THE CAEBONIFEROUS SYSTEM. 



and lacertian, in so far as our experience of modern animals is con- 

 cerned. It would, however, accord witli observed facts in relation 

 to other groups of extinct animals, that the primitive batrachians of 

 the Coal period should embrace in theu- structures points in after times 

 restricted to the true reptiles. On the other hand, it would equally 

 accord with such facts that the first-born of lacertians should lean 

 toward a lower type, by which they may have been preceded. My 

 present impression is, that they may constitute a separate family or 

 order, to which I would give the name of Microsauria, and which 

 may be regarded as allied, on the one hand, to certain of the humbler 

 lizards, as the Gecko or Agama, and, on the other, to the tailed 

 batrachians. 



It is likely that Hylonomus LyelU was less aquatic in its habits 

 than Dendrerpeton. Its food consisted, apparently, of insects and 

 similar creatures. The teeth would indicate this, and near its bones 

 there are portions of coprolite containing remains of insects and 

 myriapods. It probably occasionally fell a prey to Dendrerpeton^ as 

 bones, which may have belonged either to young individuals of this 

 species or to its smaller congener H. Wymani, are found in larger 

 coprolites, which may be referred with probability to Dendrerpeton 

 Acad'ianum. 



Hylonomus Aciedentatus, Dawson. 



This species is founded on a single imperfect specunen obtained by 

 me at the Joggins in 1859, and described in the Journal of the Geo- 

 logical Society, vol. xvi. In size, H. aciedentatus was about twice 

 as large as the species last described. Its teeth are very different in 

 form. Those on the maxillary and lower jaw are stout and short, 

 placed in a close and even series on the inner side of a ridge or plate 

 of bone. Viewed from the side they are of a spatulate form, and 

 present a somcAvhat broad edge at top, as in Fig. 145. Viewed in 

 the opposite direction, they are seen to be very thick in a direction 

 transverse to that of tlie jaw, and are wedge-shaped. There are 

 about forty on each side of the mandible, and about thirty on each 

 maxillary. 



Since the publication of my previous paper, I have ascertained 

 that the intermaxillary bones bore teeth of a peculiar form. They 

 are larger than the others, thick and coming to a blunt point, which 

 is seamed icifh longitudinal and slightly spiral ridges. This singular 

 tooth must have been a most efficient instrument for crushing and 

 penetrating the coats of crustaceans and insects, or the bony armour 

 of the smaller ganoid fishes. Remains exist at the extremity of the 



