Cope. | 188 [ Nov. 2, 
large for the animal to which the vertebra pertained, but the proportion is 
not different from that which I describe below in the genus Hryops. 
The surface of the centrum is smooth and is without grooves. The 
diapophyses and parapoyhyses are rather elongate, and are closely approx- 
imated one above the other. The superior process issues from the centrum 
opposite the superior margin of the articular faces. They stand equidis- 
tant from the extremities of the centrum, and are directed obliquely back- 
wards. The anterior zygapophyses occupy the same level. The neural 
spine is a compressed longitudinal ridge ; it divides behind, leaving a notch 
between the posterior zy gapophyses. 
Measurements. M 
lorkernchie sce beéaGncc Soane Alltel) 
Diametenotecentrum: —sVerticaleteeadeeeloe eens 0025 
WWE Goons ooncQo0a aO0K .0025 
Depth of centrumi/and neural archi... sc cio eles .0060 
Width with transverse processes...........ceesecees .0070 
Expanse of posterior zygapophyses...............-.- .0050 
The mandibular ramus which accompanied one of the vertebre is shal- 
low and stout. Its external surface is sculptured with sharp longitudinal 
ridges, which inosculate more or less. The teeth have cylindric roots 
which occupy shallow alveoli sunk in a plane surface. The crowns are 
rather elongate and compressed near the apex, and without grooves or 
serre. In contact with the jaw is an osseous fragment with a pitted or 
reticulated surface. 
Depth.ofi- ramiusics [225 sovcrerooraretooes cis aero eel: .9030 
ene th’ of crowaOfitootherccnientrietiele eit ce -0023 
EOur teeth: ines 5.3 eicts since eerie she ereeuerstaceelcvore itches -0040 
ERYOPS MEGACEPHALUS Cope gen. et. sp. nov. 
Char. gen. The details of the structure of this genus are derived 
from an almost entire cranium with underjaw, which is accompanied 
by numerous vertebree and other bones. The form is Labyrinthodont, and 
embraces the largest species of that group yet known from this continent. 
The skull is not elongate, and the quadrate bones are produced far 
backwards. The epiotic processes are present but not remarkably elon- 
gate. The temporal fossa is covered in by the usual roof. The orbits are 
round, posterior in position, and small. There is no postorbital depression 
or groove, and the lateral epiotic sinus is not deep. The nostrils are large 
and widely separated. There is no angular process of the mandible. The 
maxillary teeth are of different sizes, although arranged in a single row. 
The posterior are small and not closely placed ; large teeth appear anterior 
to the middle. The premaxillary bone supports a number of large teeth. 
Those of.the mandible which are visible in the specimen in its present 
state, those opposite the nares, are of medium size. The form of the 
crowns of the teeth is conic, with weak fore and aft cutting edges. There 
