Co7itrihution,'i to South African Vertebrate Palaontologij. I. 193 



inferior notch 137 mm. The greatest length is 310 mm. The 

 ischium resembles in its anterioi' half that of both Stagonolaiiis 

 and Bclodon, but differs from them in having the posterior part 

 expanded. 



The pubis is an extremely interesting bone, not only because it 

 gives us a clue as to how the tri-radiating pelvis was formed from 

 the plate-like type, but also because it for the first time enables us 

 to fully understand the Phytosaurian pelvis. The pubis may be 

 described as an irregular, oblong-shaped bone with one corner bent 

 back so that the inner edge of the upper part is nearly at right 

 angles to the inner edge of the lower. Fortunately it is nearly per- 

 fect, only a part of the inferior end and a little piece of the upper 

 and outer angle being missing. The upper border forms an articu- 

 lation with the ilium and with the ischium, the acetabular portion 

 being smaller than in the case of the other bones. The greatest 

 thickness of the upper end of the pubis is 67 mm. Close to the 

 inner end of the iliac articulation there is a moderate-sized oval 

 pubic foramen ; it is formed entirely by the pubis, but is almost at 

 the edge of the bone. The infra-acetabular portion, which articu- 

 lates with the ischium, measures about 85 mm. The symphyseal 

 portion of the pubis has the upper part nearly at right angles to the 

 lower, and owing to this bend the latter points almost directl)^ down- 

 wards. Were the pubis flat it would resemble the ordinary plate - 

 like type of the earlier reptiles, and so would the ischium ; the 

 difference is almost entirely due to this bending of the pubis. 

 Perhaps we' have in the notch in the symphyseal portion of the 

 ischium the first indication of a tri-radiating type beginning to form 

 from the plate-like type. As it is, Erythrosuchus must be regarded as 

 having a pelvis which is a slight modification only of the plate-like 

 type. The pubis differs considerably in appearance from that of 

 Belodon, in which the lower end is much broader and in which 

 there is not the marked twisting seen in Erythrosuclms. INIarsh 

 gives a restoration of the pelvis of Bclodon which would resemble 

 that of Erythrosuchus fairly closely were the pubis and ischium bent 

 under more than is the case. 



Veetebk-e. 



There is one well-preserved vertebra which is either a lower 

 cervical or upper dorsal. In general appearance it presents much 

 similarity to the dorsal vertebra of a carnivorous Dinosaur. The 

 centrum is amphiplatyan, about as deep as broad, and considerably 



