278 
PROFESSOR H. G. SEELEY ON THE STRUCTURE, ORGANIZATION, 
It approaches so nearly to Mammals like the Opossums and some of the larger Bats 
in form of the skull, that demonstration of the presence of typical Beptilian characters 
was needed to justify the placing of Galesauriis among Reptiles. I regard it as differing 
from the Dicynodontia, as represented by Dicynodon, in sub-ordinal characters ; for, 
although the skull seems at first sight so dissimilar, yet in essential characters there 
is no structural difference which would constitute an ordinal group. Among the 
more striking characters by which Galesaurus differs from the Dicynodonts are ;— 
First, the possession of incisor teeth, and, secondly, by the development of cuspidate 
molar teeth. No Dicynodont is known in which teeth of either kind occur, and, 
therefore, the character is so far a good one ; but, as it only extends to the dentition 
which was represented in Dicynodon by canines, I am unable to regard it as more 
than a sub-ordinal difference. Yet no existing group of Reptiles shows a sub-ordinal 
character of the same kind; but among Mammals a total absence of teeth in Ant- 
eaters only separates them as a sub-order from Armadilloes. 
Secondly, the lower jaw has the coronoid process rising above the middle of the 
orbit, and is entirely Mammalian in form. The dentary bone appears to form the 
coronoid process, though it does not reach back to the articulation, and the lower jaw 
is certainly composite. As in Carnivorous Mammals, there is no heel prolonged 
beyond the articulation, and the articular process is only slightly inflected inward. 
Thirdly, there is no descending tympanic process of the skull like that seen in 
Dicynodonts; and on this character depends the backward extension of the jugal arch 
by its squamosal element to the articulation for the lower jaw, which it contributes to 
form, though the quadrate bone still remains, though of small size, seen on the 
posterior aspect of the skull. 
Fourthly, there is a manifest difference from Dicynodonts in the occipital articula¬ 
tion, though it is imperfectly exposed, for there appears to be no trace of a basi- 
occipital condyle. 
Nythosaurus larvatus (Owen) is a Galesaurus. It agrees with the type skull in 
size and form of the cerebral region. Its molar teeth show three or four denticles, 
and appear to be about eight in number. The dentary bone similarly extends far 
back, and forms the coronoid process. A perfect mould is preserved of the auditory 
region, and shows the vertical semicircular canal and the horizontal semicircular canal 
of the auditory region (Plate 9, figs. 5, 6). The former passes outward, backward, 
and downward, and from its base the latter extends horizontally forward. On the 
right side there is indication of a third canal, directed forward at light angles to the 
posterior vertical. 
Relation of the European to the South African Anomodonts. 
Kutorga, Fischer, Eichwald, and von Meyer have described and variously 
interpreted Reptiles from the Permian rocks of Orenburg, some of which have been 
