20 
It is as yet very difficult to compare the scattered and imper- 
fectly known remains which are daily discovered. Lastlj^ 
five new genera of amphibia have been discovered in the 
Kilkenny coalfield. These are described and figured in vol. 
xxiv. of the Roj^al Irish Academy, by Professor Huxley. 
An abstract of this paper is to be found in the Geological 
Magazine for April, 1866. In all, three genera of vertebrata 
higher than fishes have been found in the carboniferous 
strata of Germam^, viz., archegosaurus, sclerocephalus, and 
apateon ; six are described from Great Britain, viz., paraba- 
trachus, anthracosaurus, loxomma, pholidogaster, pteroplax, 
and anthrakerpeton ; five from the Kilkenny coalfields, viz., 
urocordylus, ophiderpeton, ichthyerpeton, keraterpeton, and 
lepterpeton ; and five from ^N'ova Scotia, viz., baphetes, rani- 
ceps, dendrcrpeton, hylerpreton, and hylonomus. How many 
of this formidable list mil stand the tests of time aiid further 
investigation is most uncertain. 
Nearly all the peculiarities which I have enumerated serve 
to approximate our specimen to archegosaurus and the 
triassic labyrinthodontia. The position of the whole group 
is somewhat disputed. You are familiar with the toad-like 
restoration of labyrinthodon which Professor Owen has put 
forth. You are, perhaps, also aware that Professor Huxley 
(on this point as on most others) entertains a difierent opinion, 
assigning to labyrinthodontia a distinct order of amphibia, 
co-ordinate with batrachia, sauro-batrachia and ophiomorpha, 
and ranking the labyrinthodonts as urodele rather than 
anourous. If we accept this provisional arrangement, we 
have a group (labyrinthodontia) characterised by the hard, 
polished and sculptured cranial plates, two sets of teeth 
(vomerine and palatine) in the roof of the mouth, three pec- 
toral plates, bi-concave vertebral centra, weak, natatorj^ limbs 
and labyrinthoid teeth. This order is further divided by 
Professor Huxley into two sub-orders : mastodonsauria. 
