THE MICROSAURIAN FAMILY HYLONOMID^. 83 



folded. Maxilla furnished with similar teeth, one of which near the front is larger 

 than the others. Palatal teeth numerous, small, conical, with a few large teeth at 

 the sides. 



Vertebrae short, cylindrical, well-ossified, with well-developed zygapophyses and 

 neural spines; ribs strong and much curved, with well-developed division of the 

 proximal ends; pelvis imperfect, but apparently large, with broad ilium. 



Humerus half the length of the mandible ; radius half as long as humerus ; femur 

 very large and stout, nearly as long as the mandible; leg bones and phalanges corre- 

 spondingly stout. 



The thoracic plate (plate 7) is indicated only by some fragments. The abdom- 

 inal 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 radius 1.5 cm. 



Length of largest tooth 5 mm. Length of vertebra 6 mm. 



I.,ength of femur 3.5 cm. Length of rib 3 cm. 



Length of tibia 2 cm. Length of scales 5 to 7 mm. 



Length of humerus 2 cm. 



Hylerpeton longidentatum Dawson. 



Dawson, Am. Jour. Sci. (3), xii, pp. 440-447, 1876. 



Dawson, Phil. Trans. Roy. Soc. London, 1882, pt. 11, p. 640, pi. 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 II.) 



Horizon and locality : Coal formation at the South Joggins, Nova Scotia. 



Head much elongated, with the bones minutely pitted, and with delicate 

 microscopic striai, 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. 



Vertebrae short and stout, and apparently well ossified. Ribs long, with 

 double head and much curved. Humerus longer than femtir, which is short and 

 stout, if the bone taken for it is rightly determined. Abdominal scales narrow, 

 oat-shaped; thoracic plate large, broadly oval. 



Measurements of Hylerpeton longidentatum Dawson. 



Length of mandible 4 cm. Length of femur (?) 1.2 cm. 



Length of vertebra 5 mm. Length of tibia 8 mm. 



Length of rib 3 cm. Length of mandibular teeth 3 mm. 



Length of humerus i-S cm. 6 to 7 teeth in i cm. 



Hylerpeton intermedium Dawson. 

 Dawson, Proc. and Trans. Roy. Soc. Canada, xn, p. 75, 1895. 



Type: Specimen No. 3061-5, Peter Redpath Musetim, McGill University. 

 Horizon and locality: Coal formation at the South Joggins, Nova Scotia. 

 This species is known only by the mandibles and portions of the skull, which are 

 rather shorter than those of adult individuals of the last species. The extremity of 



