1878.| . 515 [Cope. 
DIMETRODON GIGAS. Sp. nov. 
Clepsydrops gigas. American Naturalist, May, 1878, p. 527. 
This animal is only represented in my collection so far by a large part 
of the pelvis. This is of the same character as that of the C. natalis, but 
differs in several details of form and is three times as large in linear meas- 
urements. The portion anterior to the acetabulum is shorter than in the 
C. natalis, and relatively deeper. The raised borders of the acetabulum 
unite, and form a thick obtuse horizontal crest, which continues to the 
apex, which consists of a broadly expanded shovel-like projection. This 
symphyseal portion is quite elongate, and carries on its supero-anterior 
face an obtuse median keel. The opposed elements diverge above the 
anterior part of the acetabulum. The latter is shallow but entire ; its most 
prominent borders are the anterior and postero-inferior. 
Measurements. M. 
Length from posterior border of acetabulum forwards... .200 
Lone diameter of acetabulum. 1). 0. 5...) es eee .100 
Total vertical diameter tu superior border of acetabulum .155 
Lensthiof anterior Sy Mi pn ysidies oir. ie ecu sss vive cwses 175 
EPICORDYLUS ERYTHROLITICUS. Gen. et sp. nov. 
Char. Gen. Epicordylus is known from a large part of the vertebral 
column, including all the regions excepting the cervical, so far as at present 
appears. In general the vertebre resemble those of Clepsydrops, having 
well-developed intercentra. The diapophyses are at the base of the neural 
arch, and are prominent, and with large undivided articular extremity ; 
they are not present on the caudal vertebre. 'The neural spines are com- 
pressed below and enlarged transversely above, so as to be claviform. 
They are not elongated over the lumbar or sacral regions, but are similar 
to those of the dorsal vertebra at those points. The ossa tii resemble those 
of Clepsydrops. The zygapophyses are as usual oblique upwards and out- 
wards, and the centra are not shortened. 
Char. Specif. The centra area little compressed, and higher than wide. 
In the anterior caudal region they are a good deal more compressed. 
The intercentra in a part of the dorsai series are larger than in any known 
species of Clepsydrops. The neural spines are bilobed at the apex on the 
sacral region, and become shortly bifurcate on the caudal series. 
Measurments. M. 
Length of a series of seventeen dorsal vertebre......... .610 
‘s an. anterior neural spine... ...s..ceecse cease .050 
ee POSLCTION ioe eas < reytiss deiaietete Shiai. ate 3 QA oie .070 
oc tubercular costal face of anterior dorsal..... .020 
5k ce Hs on seventh vertebre of 
thejseres: frome theslastas sesame eicicll« 2-1 .035 
ee five caudal vertebre of probably the same 
CTonnoo I Oy May aici ee c Casa bcerd CLERC .180 
Elevation of fourth caudal neural spine.............++: 057 
