H. G. SEELEY ON EHAMPHOCEPHALUS PRESTWICHI. 27 



3. On Rha3iphocephalt7S Prestwichi, Seelei/, an Oektthosatjeian 

 from the Stokeseield Slate o/Kineton. By H. G. Seelet, Esq., 

 F.R.S., F.G.S., Professor of Geography in King's College, London. 

 (Eead June 25, 1879.) 



Prop. Peestwich has obtained from the Stonesfield slate of Kineton, 

 near Stow-on-the-Wold, a small slab which makes a valuable con- 

 tribution to our knowledge of the structure of the skull in Ornitho- 

 saurs from the British Lower Secondary rocks. This specimen is 

 little more than a cast from the upper surface of the cranium, not 

 unlike in general character to the form originally described by 

 Goldfuss as Ornithoce^halus Munsteri. The skull itself was un- 

 fortunately in the corresponding slab, which has not been preserved ; 

 but a few slight fragments of bone remain sufficient to show the 

 dense osseous tissue which is usual in Pterodactyles. The specimen 

 yields a clear impression, which displays the proportions of the 

 cranial bones, and the sutures between them, in a way so distinct 

 as to enable me to state that this animal was certainly different 

 generically from every other type which has hitherto been described. 

 Whether, however, it pertained to a distinct species from those in- 

 dicated by the fossils from Stonesfield which have already been 

 figured by Professors Huxley and Owen is a matter upon which 

 some doubt may be felt ; but bearing in mind the relatively large 

 size of the jaws and teeth in those fossils, I am strongly of opinion 

 that this specimen indicates a smaller kind of aiiimal, in which the 

 dentary apparatus was less developed, and I therefore venture to 

 suggest for it a specific name. 



The remarkable feature which leads me to consider this specimen 

 to be the type of a new genus is its singular analogy to the Croco- 

 dilian skull, which has never been displayed to the same degree in 

 any other Ornithosaur. The fragment shows the parietal, frontal, 

 prefrontal, and i:i^sal bones ; all these are arranged on the Crocodilian 

 plan, and yet the proportions of the parietal and frontal regions are 

 in no respect those of a Crocodile. All the bones are smooth on the 

 upper surface. The parietal region is long, flattened above, slightly 

 convex in length, with a moderate median depression posteriorly, 

 where there are some longitudinal striations, as though the end of a 

 Bupraoccipital here overlapped the parietal bone; but the bone 

 terminates transversely in a sharp clean posterior edge, which is 

 sinuous, being convex in the middle and concave towards the sides, 

 where the bone widens out, giving off lateral wings towards tbo 

 squamosal region. The median suture of the parietal bones can 

 be traced, though it is not quite in the middle line. The bones be- 

 come constricted from side to side, the constriction being greatest 

 behind the middle, where they appear to be naturally notched on 

 each side. I do not see the signification of these notches, unless 

 they indicate the anterior termination of squamosal bones which 



