318 THE AMERICAN NATURALIST. [VoL. XXXII. 
In the palate, however, the theriodonts are more mammalian, 
since the palatine bones meet in the median line defining the 
posterior nares. In both types the orbits are closed posteriorly 
by the postorbitals and postfrontals. The zygomatic arch in 
both has a large malar as well as a large squamosal. 
The shoulder girdle in both presents a metacoracoid and 
epicoracoid, the latter perforated by a foramen, as well as a 
clavicle and interclavicle, 
thus strongly resembling 
the monotreme type. Di- 
cynodon, like Gomphogna- 
thus among the theriodonts, 
has a decidedly promam- 
malian type of humerus, 
with a prominent deltopec- 
toral crest, an entepicondy- 
lar foramen, and prominent 
ent- and ectepicondyles. 
The pectoral arch exhibits 
a a narrow scapula and large 
L a E pi and metacoracoids 
ischium, obturator foramen. (About 4 natural entering also into the glen- 
size. After Seeley.) : < 
oid fossa. The pelvis shows 
an ilium expanded above, a ventrally united ischium, and pubis 
with a rudimentary obturator foramen, all three bones entering 
equally into the acetabulum. 
It is clear that the dicynodonts and theriodonts hail from a 
common stock, the superorder Thermora of Cope, the former 
showing the greater specialization and aberrancy. To this 
superorder the term Anomodontia is given by most English 
authors, but it is inapplicable, because Owen invariably defined 
the Anomodontia in such a manner as to embrace only the 
dicynodonts. The first comprehensive term was that given by 
Cope. 
III. ORDER THERIODONTIA, OWEN. 
It is a most striking fact that the theriodonts proper appear 
to include two suborders, which, so far as we know, are as 
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