Cope. ] 520 {April 5, 
the absence of lateral and inferior edges, and the narrow reflected portion 
of the anterior border for the capitular facet. The diapophyses are short. 
and the tubercular surfaces not much extended. The zygapophysial sur- 
faces are but moderately oblique. The sides of the centrum are gently and 
uniformly concave, and the inferior middle line is obtuse and not promi- 
nent. 
The centra of the smaller specimens alluded to, are a little depressed, 
and may pertain to another part of the column. 
Measurements. M. 
antero-posterior ........ Chee .021 
Diameters of centrum ~ transverse.........--..--.--e0- .022 
( CTALGA Mivels sitotee cP oreieieie = oleate eye cll 
Expanse of anterior zygapophyses.........+.eesse ee eee .019 
Wadthiot neucalkcanal essere ee see eee er etka ital -009 
THEROPLEURA TRIANGULATA. 
The centra of the vertebre of three and probably four individuals repre- 
sent this reptile. The superior part of these resembles that of the 7. uni- 
formis in lacking the angle posterior to the diapophysis seen in the PL. rei- 
roversa, and in the small extent of the capitular rib-facet. The inferior 
part of the centrum differs in the presence of three longitudinal rib-like 
angles, separated by two latero-inferior shallowly concave faces. The 
median rib is not very prominent, is obtuse, and concave in profile. The 
articular faces are relatively rather wider than in the vertebrae described as 
typical of the two species preceding ; but in one vertebra (No. 2) the pro- 
portions are nearly the same. 
In the second vertebra mentioned the neural arch is entirely preserved. 
The diapophysis is at its base, and of small size; the vertebra is from not 
behind the median dorsal region. The neural spine is compressed and 
elevated, and with narrow, truncate apex. The articular faces of the zyg- 
apophyses are nearly horizontal. 
Measurements. M. 
antero-posterior............ .018 
Diameters centrum No. 1 < transverse .........5....... O17 
NA IANICHH LS SA a aro eScmc oC .016 
antero-posterior. ./.-.)-el o .023 
Diameters centrum No. 2 < transverse .............--- .024 
( ACMUEMS Seo a bc POO aC DOOC 026 
Expanse of anterior zygapophyses. ........--++s2ee-eee 020 
Elevation of neural spine above zygapophyses.......... .052 
TORATG Lan ARR Ag SuaiAt { foreiand atts. ct ties ae ele 016 
LAU VETS @ areveteretetelaleyattelel tebe 007 
BATRACHIA. 
ERYOPS MEGACEPHALUS Cope. Proceed. Amer. Philos. Soc., 1877, p. 188. 
To the characters which I have ascribed to the genus Hryops as above 
cited, I now add the following. A series of a few large teeth much exceed- 
