ON THE CLASSIFICATION OF THE LABYRINTHODONTS. 181 
APPENDIX. 
In this appendix are recorded various published genera, which are either 
founded upon very imperfect examples or are insufficiently described by the 
authors for the purposes of a classification. Hence some are not known to 
be Labyrinthodonts at all; others, while doubtless belonging to the order, 
cannot be satisfactorily placed; and a third class are of doubtful distinctness 
from previously published genera. The genus Ichthyerpeton might fairly 
have been placed in the appendix, for we know very little about it. The 
reader will regard its insertion in a provisional group (p. 166) as a mere 
suggestion, which may be adopted or discarded when more perfect specimens 
haye been brought to light. 
Some of the American descriptions have the air of rapid determinations 
published to save priority. In the absence of figures, and without an oppor- 
tunity of examining specimens, we have often been unable to recognize any 
characters of systematic value in these genera and species. When Prof. 
Cope’s detailed account of the Carboniferous Amphibia of Ohio shall appear*, 
we hope that these difficulties will be removed, and that the important Laby- 
rinthodont fauna of the United States will then render its full service to 
paleontology. 
Amphibamus, Cope. 
Skull broad. Orbits large, rounded. Premazille each with 11 or 12 teeth. 
“The integument of the head was squamous. .... The dentition is pleurodont ; 
the teeth are only visible on the mandible and the outer edge of the upper jaw; 
they are there of but one kind, small, closely set, acute-conic, not compressed, 
hollow, and without any inflections of the enamel” f. 
The dorsal vertebrze were originally described as opisthoccelian}, without traces 
of ribs or transverse processes. ‘‘ The impression of a sacral vertebra is distinctly 
preserved.” Centra of caudal vertebrae probably unossified ; of the neural spinous 
processes of the caudal vertebrae “ twelve very distinct impressions may be counted 
to the sacral region; the posterior are most slender, the median most elevated, the 
anterior lower and of greater longitudinal extent.” Inferior arches were probably 
present in the caudal region. 
“ The anterior limbs were short and weak.” Humerus slender, not much dilated, 
without condyles. Ulna and radius separate and slender. ‘The femur is slender, 
much dilated distally, slightly curved in the posterior direction, and without con- 
dyles..... The tibia and fibula are one half the length of the femur, are slender, 
most dilated proximally..... The tarsus was probably cartilaginous. .... The num- 
ber of phalanges is 3, 3, 4, 5,4. ....The terminal phalanges are elongate acute.” 
‘« A few traces indicate that the dermal integument was covered, on the anterior 
es of the body at least, with small and subangular scales, There have been ab- 
ominal scales arranged in narrow imbricate series, directed inward and posteriorly. 
Traces of plates are wanting, excepting a smali fragment lying beside the cervical 
vertebrze.” 
Professor Cope believes that the iris and pigmentum nigrum of the eye are pre- 
served in the fossil. A median lenticular vacuity is “ obviously the vertical pupil 
of a nocturnal animal. .... These appearances cannot be explained on any suppo- 
sition of artificial production.” 
“This animal combines with its Batrachian, a few Lacertilian characters, having 
some resemblance to Dawson’s genus Hylonomus, and much affinity with Prof. 
‘ * Paleontology of Ohio, vol. ii. (unpublished). + Peripheral layer of dentine? 
¢ This was afterwards found to be erroneous. “There were actually, however, only 
osseous neural arches present ; and I am now decidedly of the opinion that the vertebral 
centra were either cartilaginous or annuliform, as in Archegosaurus,’—Cope, Synopsis, 
p. 8. 
