214 PROCEEDINGS OF THE ACADEMY OF 



tinctfrom the last. The muzzle is not so broadly rounded, and the premax- 

 illary teeth are relatively much larger. The sculpture is more delicate, with 

 the ridges more acute. The orbits and nares are not defined. The maxillary is 

 well preserved for a length of an inch ; its teeth are smaller than the^remax- 

 illaries ; I count four in a line ; crown simple conic. External surface of 

 maxillary not very strongly sculptured. 



This species cannot be referred to its genus without further material. I 

 therefore do not name it, hoping to avoid the unworthy practice of some, who 

 g'we prospective names — to be applied to other peoples future discoveries, and 

 the like. 



Dendrerpeton acadianum Owen, Quart. Journ. Geol. Soc, x, 1853, 81. Daw- 

 son loc. cit. 

 Coal Measures : Joggins of Novrf Scotia. 



Dendrerpeton owenii Dawson, Canadian Naturalist and Geologist, viii,161. 

 Coal Measures : as the last. 



HYLERPETON Owen. 

 Hylerpeton dawsoni Owen, Journ. Geol. Soc. Lond., 1862, 241. Dawson, 

 Canadian Naturalist and Geologist, viii, 272. 

 Carboniferous Coal Measures. The Joggins, Nova Scotia. 



BRACHYDECTES Cope. 



This genus is indicated by two rami of a mandible, and a portion of a pre- 

 maxillary only. These, when compared with those of Oestocephalus and Dendrer- 

 peton from the same locality, and with others described by authors, are so 

 much stouter, i. e. shorter and more elevated, that they evidently pertained to 

 a genus not hitherto known. The genus further differs from Oestocephalus in 

 having the teeth of equal size to the posterior parts of the series, that is to the 

 base of the elevated coronoid process. The teeth are elongate cylindric cones, 

 with their acute tips turned a little posteriorly. The fractured ones display a 

 large pulp cavity. The three premaxillaries preserved are similar but without 

 curvature of the tips. They do not exhibit striae or any other sculpture. So 

 far as the remains known go, the genus is nearer Hylerpeton than any other. 

 The latter does not give any indication of the very elevated coronoid process 

 of Brachydectes, though the external portion of the dental bone in that region 

 being lost, little can be said about it. Prof. Owen's plate indicates a ramus 

 whose depth at the last tooth enters SJ times the total length. In our species 

 this depth enters about five times. There are at least nine teeth in the Nova 

 Scotian species ; seven in the present one, 



Brachydectes newberryi Cope. 



This species is represented by one nearly perfect ramus mandibuli, one den- 

 tary bone, and one premaxillary probably not complete. 



The dentary bone appears to have been attached by suture to the articular 

 and angular, as its free margin has very much the outline of that suture in 

 Amphiuma and lizards. The coronoid process would also seem to be a part 

 of the same bone as in Amphiuma and Menopoma, and not composed of a 

 coronoid bone as in lizards. It rises immediately behind the last tooth, and 

 displays no suture. 



The lower portion of the dentary is prolonged into an acute angle. This is 

 separated by a deeji and wide concavity from the superior posterior prolonga- 

 tion, which is obtuse and rises at once into the coronoid process. Teeth on 

 this dentary seven ; the same number is on the preserved ramus ; this number 

 I suspect to be complete or nearly so. The teeth terminate at the obvious 

 termination of each ramus, which is it is true slightly obscured. The teeth 

 are the longest of the Microsauria in relation to the depth of the ramus, equal- 

 ling the largest in Ophiderpeton. They are doubtless exposed, as are some of 



[Sept. 



