80 THE COAL MEASURES AMPHIBIA OF NORTH AMERICA. 



Hylonomus Utidens Dawson. 



Dawson, Phil. Trans. Roy. Soc. Ix>ndon, 1882, pt. 11, p. 637, pi. 39, figs. 18-22. 

 Dawson, Proc. and Trans. Roy. Soc. Canada, 1895, p. 74. 



Type: Specimen No. 3061-1, Peter Redpath Museum, McGill University. The 

 British Museum (393, pt. iv, p. 224) also has a specimen. No. R 447. 



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



Fragments of 3 specimens from 3 trees represent this species (plate 10). It seems 

 to have been of stouter build than //. lyelli, with the limbs shorter in proportion. Its 

 generic affinities are somewhat doubtful, as it presents in some respects characters 

 intermediate between Ilylouomus and Ilylerpeton. 



Mandibular and maxillary teeth broadly conical, about 20 in each mandible — 

 3 in I mm. ; anterior mandibular teeth somewhat larger than the others, and bent or 

 hooked. Vomer or palate with minute teeth. Thoracic plate large. Scales of abdo- 

 men oval, but somewhat narrow, and tending to be oat-shaped. 



Length of mandible (imperfect) mm. 9 Lengtli of tibia (.■') mm. 5 



Length of humerus mm. 7 Length of thoracic plate cm. I 



Length of vertebra mm. 2 lycngth of six caudal vertebrae mm. 8 



Hylonomus multidens Dawson. 



Dawson, Phil. Trans. Roy. Skx:. London, 1882, pt. 11, p. 637, pi. 39, figs. 23-26. 

 Dawso.n, Proc. and Trans. Roy. Soc. Canada, 1895, p. 74. 



Type: Specimen No. 3061-2, Peter Redpath Museum, McGill University. 



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



This animal is known only by portions of bones of the head and a few other frag- 

 ments. The scattered bones of the extremities are inseparable from those of //. lyelli 

 occurring with it. As compared with that species, the bones of this are smoother 

 and more delicate. The teeth are more numerous and slender. The crushed distal 

 end of a femur or humerus found near the skull indicates that the limbs were well 

 developed. 



mm. 



Length of mandible 1 1 



Length of skull 15 



Length of femur 9 



Teeth, 5 to 6 in i mm. 



Hylonomus wymani Dawson. 



Dawson, Quart. Jour. Geol. Soc. London, -xvi, p. 277, figs. 27-29, i860. 

 Dawson, Air-breathers of the Coal Period, p. 52, 1863. 



Dawson, Phil. Trans. Roy. Soc. London, 1882, pt. 11, p. 637, plate 39, figs. 15-17. 

 Dawson, Acadian Geology, 3d ed., p. 378. 



Type: Specimen No. 3061, Peter Redpath Museum, McGill University. There 

 is also specimen No. R 446 in the British Museum (393, pt. iv, p. 224). 



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



As compared with the //. lyelli the present species is smaller in size, more elon- 

 gated in form, had the teeth less numerous (about 22 in the mandible), and shorter 

 and more obtuse in form. There are 6 to 7 in i mm. 



This species is much more rare than //. lyelli, but quantities of minute bones, 

 probably belonging to it, occur in the coprolitic matter. In one specimen 38 verte- 



