AND AVES OF NORTH AMERICA. 9 



P ELI ON, Wyman. 



Proc. Acad. Natl. Sci. Philadelphia, 1868, p. 211. Raniceps, "Wyman Amer. Journal Sci. and Arts, 1858, p. 158. 

 Not of Cuvier, (Pediculati.) 



PELION LYELLII, Wyman. Raniceps lyeelii, Wyman, I. c. 



This animal differs from the genus Amphibamus, in the well ossified vertebral axis; 

 no remains of a tail with elevated neural spines exist in the type specimen, nor have 

 ventral scales or sclerotic bones been seen. 



Middle Coal Measures, Jefferson county, Eastern Ohio. 



HYLONOMUS, Dawson. 



This genus embraces the smallest species of the order. They all pertain to that 

 interesting Batrachian fauma of the Coal Measures of the Joggins of Nova Scotia, eluci- 

 dated chiefly through the exertions of Principal Dawson, of Montreal. This fauma 

 embraces six of the Microsauria and one true Labyrinthodont. Of the former, the 

 Hylerpeton dawsonii Owen, is the largest species, the Dendropetons next, and the 

 Hylonomus wymanii is the smallest. As Dr. Dawson has described these curious 

 animals in the " Canadian Naturalist," in detail, I will not repeat them here, but add a 

 list expressing some peculiarities of dentition, which are highly important in the deter- 

 mination of species. This, giving the number of teeth in a line of 1-1 2th of an inch, has 

 been furnished me by Prof. Dawson. 



HYLONOMUS LYELLII, Dawson. 

 Loo. Cit. VIIL, 167, Coal Measures of Nova Scotia. 



HYLONOMUS ACIEDENTATUS, Daivson. 

 Loc. Cit. VIIL, 258, Coal Measures; with the last. 



HYLONOMUS WYMANII, Dawson. 



Loc. Cit. VIIL, 270, Coal Measures ; with the last. 



2Fo. of Teefli in Line. 

 Dendrerpeton acadiannm. 



Outer series of teeth, 4 teeth in one line to lj line. 



Inner do. 4 in 2i lines. 

 I), owenii. 



Outer Series, 4 in one line. 



Inner do. 4 in two to 2| lines. 



Hylerpeton dawsonii, 4 in five Hues. 



Hylonomus lyelli, 12 in two lines. 



H. wymanii, 12 in H lines. 



AMEKI. PHILOSO. SOC. — VOL. XIV. 3 



