84 AIR-BREATHERS OP THE COAL PERIOD. 



species, and all being nearly, though not absolutely, of the same 

 size. It is also proper to state that in the case of the original 

 specimen, and another still more perfect one, both of which are now 

 in London, I have been able to refer only to the published plates, and 

 to add to these from parts of two additional individuals still in 

 my own collection. 



In form, Dendrerpeton Acadianum was probably lizard- like ; 

 with a broad flat head, short stout limbs and an elongated tail ; 

 and having its skin, and more particularly that of the belly, pro- 

 tected by small bony plates closely overlapping each other. It 

 may have attained the length of two feet. The form of the head 

 is not unlike that of Baphetes, but longer in proportion ; and much 

 resembles that of the labyrinthodont reptiles of the Trias (Fig. 1). 

 The bones of the skull are sculptured as in Baphetes, but in a 

 smaller pattern (Figs. 8, 9). The nostrils are small, and near the 

 muzzle : the orbits are circular, and separated by a space of more 

 than their own diameter. In the upper jaw there is a series of con- 

 ical teeth on the maxillary and intermaxillary bones (Figs. 5, 15). 

 Those on the intermaxillaries are much larger than the others 

 and have the aspect of tusks or canines (Figs. 3, 13). Within this 

 outer series of teeth, and implanted apparently in palatal bones, 

 as in Archegosaurus Decheni, there is a second series of teeth, 

 closely placed, or with intervals equal to the diameter of one 

 tooth. These inner teeth are longer than the others, implanted 

 in shallow sockets, to which they are anchylosed, and have the 

 dentine plicated, except toward the point (Figs. 2, 4, 6, 1, 17). A 

 third group of teeth, blunt at the points, largely hollow in the in- 

 terior, and with the dentine quite simple, appears in detached bones, 

 which may represent the vomer (Fig. 12). Only a part of this 

 formidable armature of teeth appears in the skull represented in 

 Fig. 1, as the bones of the roof of the mouth have been removed, 

 adhering to the opposite side of the matrix ; but the fact of the 

 occurrence of two sets of teeth was ascertained by Prof "Wyman, 

 from the original specimens, and is manifest in the fragment 

 represented in Fig. 17; while the other teeth, supposed to be 

 vomerine, appear in fragments which must, from their size and 

 collocation, have belonged to Dendrerpeton. It will be observed 

 that all these teeth are anchylosed to the bone ; and while those of 

 the vomer are thinly walled and simple, those on the maxillaries and 

 intermaxillaries are plicated toward the base only, while the inner 

 series of palatal teeth are plicated more than half way up. In 



