3- Dorsal vertebrae of equal height before and 



behind. 

 4. Sacrals united, 



SYSTEMATIC REVISION 57 



in middle; in the dorsal region the body united with the arch by suture. Two 

 sacral vertebrae. Ribs single and double head. Clavicle and interclavicle flattened 

 at the proximal ends and the outer surface with a deep-pitted sculpture. Coracoid 

 and procoracoid free. Cleithrum large, neither procoracoid nor pubis take part 

 in the articular cavities. Humerus with articular ends turned at an angle to each 

 other; foramen entepicondylum present. Digits with terminal claws. 



The following, from Stappenbeck, shows the difference between Phanerosaurus 

 and Stephanospondylus: 



Stephanospondylus. I Phanerosaurus. 



1. Neural arch co-ossified with the centrum. i. Neural arch united with centrum by suture. 



2. Centrum circular in section. 2. Centrum roundly triangular in section. 

 ~ ' ' '3. Dorsal vertebrae lower anteriorly than posteriorly. 



4. Sacrals freely movable. 



5. First sacral with large anterior and small posterior 



5. Zygapophyses of anterior sacral of equal size, j zygapophyses. 



6. Articular face for first sacral rib nearly | 6. Articular face for the first sacral rib elongate and 



square and vertical. | inclined. 



7. First sacral rib flat, both ends enlarged. 7. First sacral rib T-shaped. 



Suborder PROCOLOPHONIA (?) Lydekker. 



Genus PROCOLOPHON Owen. 



Owen, Cat. Foss. Rep. South Africa, 1876, p. 25. 

 Seeley, Trans. Roy. Phil. Soc., vol. 180, 1889, p. 269. 

 Broom, Records of the Albany Museum, vol. i, 1903, p. 8. 



Type: In the British Museum of Natural History; other specimens in the 

 Albany Museum, Graham's Town, South Africa. 



Skull, short and triangular; the sutures visible. Temporal region with a 

 doubtful temporal opening. Posterior portion of the skull excavated by an epiotic 

 notch, the quadrate not exposed. Pterygoids with external process. Parasphenoid 

 rostrum not showing on the base of the skull. Cheek teeth with broad flattened 

 crowns. Vertebrae amphiccelous, notochordal. Neural arches broad and rounded. 

 Intercentra present. Coracoid, procoracoid, and scapula separate. Ischium and 

 pubis flat and plate-like. Limbs short and stout. Humerus with entepicondylar 

 foramen. The proximal row of the tarsus with two elements, a fibulare and an 

 intermedium ulnare. Phalangeal formula 2, 3, 4, 5, 4. 



Genus THELEGNATHUS Broom. 

 Records of the Albany Mus., vol. I, 1905, pp. 269-275. 



Type: A left maxillary with teeth, the front of the right dentary, and a few 

 other fragments. Preserved in the Albany Museum, Graham's Town, South Africa. 

 From the Middle Trias of Aliwal North, South Africa. 



Original description: "In the maxilla there'are 6 and possibly 7 molar teeth, 

 and as in Procolophon they are anchylosed to the bone. In structure and shape the 

 teeth also resemble closely those oi Procolophon. They differ however, in becoming 

 steadily larger on passing back. The anteroposterior measurement of the first 6 

 molars is 17.5 mm. and all the teeth are about 4 mm. high. The maxilla is fairly 

 flat, and measures 27 mm. by 12 mm. It has two fairly large foramina, the first 

 above the interspace between the second and third molars, and the second above 

 the interspace between the fifth and sixth. 



"A second specimen shows three maxillary teeth in beautiful preservation. 

 They are probably the fourth, fifth and sixth. The fourth is 2.5 mm. by 4 mm. and 



