400 Professor E. Broom — T/ie Skull of Tapinocephalus. 



HoMALOSTEGA cuNiFOEMis, mihi. PI. XXIII, Figs. 5a-d. 

 A specimen with ooecia occurred when there was still time to revise 

 the original diagnosis {ante, p. 338) that no ooecia were known, but it 

 was too late to add to PI. XIV, Figs. 6 and 7. I now give figures of 

 some ooecia, the one figured as bh being probably perfect. 



EXPLANATION OF PLATES XXII AND XXIII. 

 Plate XXII. 

 Fig. 1. Membraniporella monastica. x 20. 

 ,, 2. Ditto, part of same specimen, x 40. 

 ,, 3. Ditto, part of worn specimen, x 20. 

 ,, 4. Membraniporella castrum. x 20. 

 ,, 5. Ditto, another specimen, x 20. 



Plate XXIII. 

 ,, 1. Cribrilina ostreicola. x 20. 

 ,,2. Ditto, another specimen, x 40. 

 ,, 3. Cribriliua subvitrea. x 20. 

 ,, 4. Ditto, part of same specimen, x 40. 

 ,, 5a-d. Homaloslega cuniforniis. 

 [To be continued.) 



lY. — On the Skull of Tapinocephalus. 



By Professor R. Broom, M.D., D.Sc, For.Corr.Z. S.Lond., Victoria College, 

 Stellenbosch, Cape Colony, South Africa. 



(with two TEXT-FIGIJfiES.) 



IIS" 1876 Owen described the tip of the snout of a large fossil reptile 

 from Soutti Africa under the name of Tapinocephalus atherstoni. 

 Although a few vertebrae and other bones of the skeleton are known, 

 as no further remains of the skull have been found we have been in 

 complete ignorance of the affinities of this one of our largest Karroo 

 reptiles. 



In the Seeley Collection in the British Museum there is a nearly 

 perfect but somewhat crushed skull which pretty certainly belongs to 

 the genus Tapinocepliahis and, although it is about one-third smaller, 

 perhaps to the type species. Another specimen shows the postorbital 

 portion of the skull. To these specimens Dr. Smith Woodward 

 has called my attention, and very kindly given me permission to 

 describe them. 



The skull consists of a broad, high, rounded posterior portion and 

 a broad, flat snout. The orbit is near the middle of the skull, and 

 there is on each side a single temporal opening, and the quadrate is 

 carried well forward and lies under the postorbital arch. The general 

 structure will, however, be better understood from the figures given. 

 Fig. 1 represents a side view of the skull slightly restored, and with 

 the distortion corrected. Many of the sutures are obscured, but 

 sufficient can be made out to leave no doubt as to the nature of the 

 skull. The temporal arch is essentially similar to that in the Thero- 

 cephalians and Anomodonts, being formed entirely by the squamosal 

 and the jugal, both of which are very large. The quadrate is also 

 large, but mainly hidden by the squamosal. Owing to the advanced 

 position of the quadrate the lower jaw must have been short, its 



