286 
PROFESSOR H. G. SEELEY ON THE STRUCTURE, ORGANIZATION, 
circumstance that'teeth occur upon the bones of the palate in Procolophon, and that 
the vomera meet the pterygoid bones with tlie palatines external to them in the same 
relative positions as in my restoration of Protorosaurus (‘ Phil. Trans.,’ B., vol. 
178 (1887), p. 205), would prepare me to find other points of correspondence in the 
skulls of those types, while the fact that the Anomodonts occur in the Permian 
rocks of France and Bussia makes an affinity with that type less improbable in the 
Thlirinoferwald Saurians. 
Comparison of the Anomodontia with the Saurischia. 
The skeleton is imperfectly known in the Saurischia in details of structure ; but the 
following resemblances may have value as showing affinity. 
The ilium in both types may be extended behind the acetabulum as well as in front 
of it; but in several genera there is a tendency for the anterior extension to be the 
more conspicuous. The pubis and ischium meet by a median vertical suture; but 
while these bones are thus united in known Anomodonts down to the median 
symphysis, there is in the Saurischia a more or less large ventral vacuity by which 
the median symphysis of the two pubic bones is separated from the corresponding 
union of the ischia. 
The larger limb bones may have much iu common, and I am aware of no satis¬ 
factory characters by which the femur, tibia, fibula, ulna, and radius could be always 
differentiated, and the humerus has enough in common to make the distinction of 
type dependent upon the absence from the Saurischia of the foramen or foramina in 
the shaft. The divergence is conspicuous in the carpus and tarsus and the smaller bones 
of the foot; and tlie scapular arch appears to be formed on a totally different plan. In the 
vertebral column there is enough in common to have led Sir B. Owen to group Pnrem- 
saurits and Tapinocepihalus the Dinosauria. The cervical vertebrae have the ribs 
articulated by two heads ; but I am aware of no evidence that any Anomodonts, 
except Pareiasaurians, have this kind of articulation in the dorsal region, and there¬ 
fore the vertebral characters will prove to lie essentially Sauropterygian, v.dth only 
such divergence as may be correlated with difference in the condition of existence. 
The resemblance which is found in the sacrum of some genera seems to me to be an 
induced resemblance, and not an inherited character. The tail is but imperfectly 
known in Anomodonts, but it is always short, and no examples of long chevron bones 
are at present known. The skull appears to be constructed upon a different plan, but 
it is only known among the Saurischia in Compsognathus and Ceratosaiir'iis, and in 
neither ty])e is the structure of the palate available for comparison. 
