mm. Entire height of vertebra 24 Width at side of neural canal 21.5 Width of neural canal 13 Height of neural canal (crushed?) 6.5 Width of vertebral centrum anteroposteriorly 5.5 Height of neural spine from top of neural canal 9 =Genus AMBLYODON Dawson, 1882.= Dawson, Phil. Trans. Roy. Soc. London, pt. 11, p. 644, pl. 40, figs. 57-61, 1882. Type: _Amblyodon problematicum_ Dawson. This genus was described by Dawson in 1882 from very imperfect remains. He says that it is "characterized by stout cylindrical teeth, blunt at the apices; but otherwise imperfectly known." =Amblyodon problematicum Dawson.= Dawson, Phil. Trans. Roy. Soc. London, pt. II, p. 644, pl. 40, figs. 57 to 61, 1882. Type: Specimen No. 3061-10, Peter Redpath Museum, McGill University. [Illustration: Fig. 38.--Skeletal elements of _Amblyodon sp._ from the Coal Measures of Nova Scotia. _a_, tooth, × 25; _b_, section of tooth, × 25; _d_, fragment of thoracic plate; _f_, shaft of limb bone; _e_, rib.] Horizon and locality: Coal Measures of Nova Scotia. A fragment of a jaw 1 cm. in length has 10 cylindrical teeth, simple and smooth, with large pulp cavities and rounded regularly at the apices. With these are 4 vertebræ of the usual type, measuring together 1 cm. Fragments of cranial bones also occur and are obscurely pitted. There is also what seems to be the shaft of a limb bone and a few oval scales. A flat and somewhat rhombic bone, with a style at one side, may possibly be a thoracic plate or possibly a parasphenoid. The material is too scanty for any satisfactory description of this animal, but it is provisionally named _Amblyodon problematicum_. CHAPTER XXIV. THE TEMNOSPONDYLOUS AMPHIBIA OF THE COAL MEASURES OF NORTH AMERICA. DEFINITION OF THE ORDER TEMNOSPONDYLIA, ZITTEL. 1887. Zittel, Handbuch der Paleontologie, Abth. 1, Bd. 3, p. 384, 1887.