The thoracic plate ([plate 7]) is indicated only by some fragments. The abdominal scales are narrow and pointed (oat-shaped), smooth externally and with a ridge at one side within. The following are the dimensions of the largest specimen:
| Length of mandible | 4.4 | cm. |
| Length of largest tooth | 5 | mm. |
| Length of femur | 3.5 | cm. |
| Length of tibia | 2 | cm. |
| Length of humerus | 2 | cm. |
| Length of radius | 1.5 | cm. |
| Length of vertebra | 6 | mm. |
| Length of rib | 3 | cm. |
| Length of scales | 5 to 7 | mm. |
Hylerpeton longidentatum Dawson.
Dawson, Am. Jour. Sci. (3), XII, pp. 440-447, 1876.
Dawson, Phil. Trans. Roy. Soc. London, 1882, pt. II, p. 640, pl. 42, figs. 86 to 109.
Dawson, Proc. and Trans. Roy. Soc. Canada, 1894, XII, p. 74.
Type: Specimen No. 3061-6, Peter Redpath Museum, McGill University. There is also a specimen, No. R 440, in the British Museum ([393, pt. IV, p. 225]). ([Plate 11.])
Horizon and locality: Coal formation at the South Joggins, Nova Scotia.
Head much elongated, with the bones minutely pitted, and with delicate microscopic strife, but not sculptured. Mandibular and maxillary teeth long and acute, pointing backwards, with the apex of their inner sides finely striated; 20 or more in each ramus of the lower jaw; palatal bones with several long, slender teeth and many minute teeth. The mandibles found are not complete, but there are indications that there was an ascending process as in H. dawsoni, but less developed. The narrowness of the dentary bone is caused in part by the lower posterior edge being bent inward and by the posterior end being broken off above.
Vertebræ short and stout, and apparently well ossified. Ribs long, with double head and much curved. Humerus longer than femur, which is short and stout, if the bone taken for it is rightly determined. Abdominal scales narrow, oat-shaped; thoracic plate large, broadly oval.