3O2 THEROMORPHA 



distal portion of the quadrate ; separate ectopterygoids do not 

 seem to be developed. The shoulder-girdle consists on either 

 side of a large scapula, which is mostly directed obliquely back- 

 wards, and is fused with the coracoid ; a precoracoid is present or 

 at least indicated by a notch or foramen ; it is usually fused with 

 the other bones. At least some genera possess a T-shaped inter- 

 clavicle and clavicles ; Pareiasaurus possesses also a pair of 

 cleithra. 



The pelvis is in every respect constructed upon the Mam- 

 malian plan. The three constituent parts meet at the ace- 

 tabulum, and the ventral bones, pubes and ischia, form one broad 

 symphysis, leaving two, sometimes very small, obturator-foramina. 

 The ilium is attached to one to five sacral vertebrae, and since 

 the whole pelvis slants obliquely downwards and backwards, this 

 sacral attachment is distinctly pre-acetabular, perhaps most 

 markedly so in Dicynodon. The limbs are mostly stout, humerus 

 and femur with strong crests ; the feet are thoroughly plantigrade, 

 with five fingers and toes. The details of the carpus and tarsus are 

 not well enough known to permit of generalisation, but there is 

 a tendency to form a heel, and to develop the cruro-tarsal 

 joint into the chief joint of the hind feet. The vertebrae are 

 amphicoelous, sometimes with rather thin-walled centra, so that 

 in these cases the chorda was continuous. Intercentral wedges, 

 or basiventral elements, are frequent in the cervical and caudal 

 regions. Most of the ribs, especially those of the neck, have a 

 tuberculum attached to the neural arch, and a distinct capitu- 

 lum which articulates either with the centrum or with the 

 intercentrum, or lastly, if the latter is absent, between two 

 centra. The axis and atlas vertebrae are united. 



The occipital condyle exhibits every stage between the single 

 median knob {Pareiasaurus} formed almost entirely by the 

 basioccipital bone, a triple condyle {Dicynodon) to which both 

 lateral and the basioccipital bones contribute, and a kidney- 

 shaped or double coudyle (Cynognatlms) from which the middle 

 or basioccipital portion is more or less withdrawn. 



Dermal bony armour reached an extraordinary development on 

 the head of Pareisaurus and Elginia ; whether other parts of the 

 body were protected is doubtful, but the flattened tops of 

 the neural spines of Pareiasaurus suggest that they carried 

 bony scutes. Abdominal protective ossifications are unknown. 



