PROF. H. G. SEELEY ON DELPHINOGNATHUS CONOCEPHALTJS. 469 



31. On Delphinognathus con^ocephalfs (Seeley) /rom the Middle 

 Kaeoo Beds, Cape Colony, preserved in the South African 

 Museum, Capetown. By H. G. Seeley, Esq., F.E.S., F.G.S., 

 Professor of Geography and Lecturer on Geology in King^s 

 CoUege, London. (Read May 25th, 1892.) 



The skull herein described is the only portion of the animal collected. 

 No locality for it is recorded in the South African Museum, but 

 Mr. Thomas Bain, the Government geologist in Cape Colony, believes 

 it to have been collected by himself from near Beaufort West. It is 

 slightly distorted with the folding of the strata. The preservation, 

 of the specimen leaves something to be desired, for the pre-orbital 

 region is more or less obscured by weathering, which has destroyed 

 the superior contour of the snout, the alveolar border, and the ante- 

 rior extremity of the jaws. The occipital condyle and much of the 

 occipital plate from the back of the skull are also lost. But, notwith- 

 standing these defects, the skuU is the most interesting Anomodont 

 preserved in Cape Colony, and indicates a new family of fossil 

 Reptilia. 



The head is characterized by its broad, high, vertical occipital 

 plate. The broad subpentagonal roof to the brain- case (fig. 2) ascends 

 laterally from the inclined temporal region, and is elevated in a cone, 

 which terminates in a large, circular, crater-like parietal foramen. 

 The skull has large sub-circular vertical orbits, placed far backward 

 above the hinder extremity of the lower jaw, so as to converge 

 forward. The temporal fossae are short and small, owing to the 

 position of the orbits and the width of the cerebral region. The 

 quadrato-squamosal region is directed obliquely forward, and forms 

 a vertical articular surface to articulate with the lower jaw, which is 

 singularly deep posteriorly, and suggests the jaw of a porpoise in its 

 form. 



The skull is now 31 centim. long, but was probably somewhat 

 longer. The occipital plate was- higher than wide. It extends 24 

 centim. above the inferior margin of the mandible. The bones 

 which compose the plate lie in a vertical plane, and are conditioned 

 as in Dicynodon and its allies, but their several limits cannot be 

 traced. The transverse measurement of the back of the head over 

 the foramen magnum is 20 centim., and at the lateral borders the 

 squamosal bones are prominent. Those bones make the external 

 narrow, vertical borders of the small temporal vacuities. The 

 vertical measurement from the base of the occipital condyle to the 

 summit of the occipital plate is 16 centim. ; the superior lateral 

 contours of the plate converge upward in half an ellipse. Inferi- 

 orly, there is only a slight narrowing caused by a slight approxi- 

 mation of the squamosal bones in the region of the condyles for 

 the lower jaw. The foramen magnum is not clearly evidenced, but 

 appears to have been small, narrow, and vertical, not more than 2*7 



