778 MR. D. M. S. WATSON ON 
‘excluded from the glenoid cavity, and there is no trace of the 
screw-shaped form of the articular surface which is an essential 
feature of the primitive type. The humerus also is of a more 
modernised form, its action being an up and down movement 
instead of one which is nearly parallel to the ground. ‘The 
very broad lower end of the clavicle of Titanosuchus is, however, 
a point of resemblance with the earlier forms. 
In the pelvic limb we find a somewhat similar mixture of 
characters. 
The whole pelvis, for example, is somewhat similar to that of 
Dimetrodon, particularly in the production of the outer corner of 
the front border of the pubis and its deflection, more so perhaps 
than to any South African type; but the femur is of a modernised 
type strongly resembling that of Dicynodon. 
The final result is that the presence of the Deinocephalia 
makes it impossible to exclude the American Lower Permian 
and Carboniferous Pelycosaurs from the later South African 
Therapsids. Such a division could at any time have been drawn 
only on the more primitive limbs and large quadrate of the early 
forms; the fact that in Deinocephalia we have types with a 
quadrate as large as that of the Pelycosauria combined with 
modernised limbs renders the foundation of a great group- 
division on these characters quite impossible. 
For this great stem ef the Reptilia, including all the mammal- 
like reptiles, many names are available. I am myself inclined to 
extend Broom’s Therapsida, a most appropriate name, to the 
whole of them, but I fully recognise that Cope’s earlier names of 
Theromorpha and Theromora have been used in the same sense ; 
these names were never very clearly defined by Cope, and have 
at one time or another included nearly all Permian reptiles. If 
anyone should wish to resuscitate these names in this connection, 
I would point out to them that Owen’s term Anomodontia was 
used by that author in 1860 in a wide sense to include the 
Dicynodonts and also carnivorous Therapsids from South Africa, 
and has at least as good a claim to be used as Cope’s later terms. 
Discussion of Special Features of the Skull. 
The septomaxilla of Deinocephalia is of interest on account of 
its variability. It resembles that of all other Therapsids, except 
certain Cynodonts and Anomodonts, in the fact that there is a 
foramen behind it opening from the outer surface into the nasal 
cavity. It is of interest that this foramen was first described by 
Case in Dimetrodon. It is evident in the majority of the more 
primitive South African “Carnivorous” Therapsids, and is clearly 
shown in a British Museum skull of Hndothiodon and in 
Prof. Sollas’s model of Dicynodon. Its function is unknown, the 
only suggestion I have yet found is that it may mean that the 
ductus naso-lachrymalis opened on the surface; it will be re- 
membered that in the small Temnospondylous Stegocephalian 
