442 Prof. H. G. Seeley on the 



end of the metacarpal of the fifth or wing- finger. I regarded 

 this fossil as part of the premaxillary of a toothless Ptero- 

 dactyle, and in the Ann. & Mag. Nat. Hist, for January 1871, 

 p. 35, remarked : — " A new genus appears to be constituted 

 by some (three) portions of jaws from the Cambridge Green- 

 sand. Unfortunately, the extremity is not preserved. They 

 have the ordinary dagger-shaped snout, but appear to be 

 entirely destitute of teeth. I provisionally name the genus 

 Ornithostomay It was only after this publication that any- 

 thing, was heard of Pterodactyls in America, and not till 1876 

 that the toothless character of their jaws was known and the 

 name Pteranodon proposed. 



Professor Marsh's material is evidently incomparably 

 superior to that which was before me; but there is, so far as 

 I can discern, no evidence of generic difference between 

 Ornithostoma and Pteranodon. If any one will turn to the 

 figure of my type (Pal. Soc. 1859, pi. iv. figs. 4, 5) already 

 quoted, and compare cither the lateral aspect, fig. 4, or the palate, 

 fig. 5 (from which the matrix there shown is now removed), 

 with Prof. Marsh's figures reproduced in the ' Geological 

 Magazine,' August 1884, p. 347, the only difference found 

 will be that the American toothless Ornithosaur is twice the 

 size of that from the Cambridge Greensand. There is perfect 

 correspondence between them in the dagger-shaped form of 

 the jaw, in the relation between the height of the jaw and 

 the breadth of the palate, in the flattened sides of the snout 

 and their convergence superiorly into a rounded ridge, in the 

 thin rounded margin to the jaw which represents the alveolar 

 border, and in the smooth palate formed by a single wide 

 tioncave channel. No palaeontologist will fail to appreciate 

 the significanceof these absolute coincidences of structure; and, 

 BO far as they go, they seem to me to indicate that Pterano- 

 don is a synonym of Ornithostoma. I record the British 

 species as 0. Sedgwicki. 



There is some other evidence which points towards the 

 same conclusion. In the ' Ornithosauria ' I figured the 

 quadrate bone and quadrato-jugal of Ornithocheirus (pi. xi. 

 tigs. 13, 14, &c.). The form of the quadrato-jugal was 

 then unparalleled ; but Prof. Marsh's figures show substan- 

 tially the same type {loc. cit.) in the American toothless 

 Ornithosaur. 



Further, Professor Marsh figures an extraordinary deve- 

 lopment of the occipital crest in this type, and the Orni- 

 thocheirus of the Cambridge Greensand gives evidence 

 of a crest having been worn away. Mr. J. F. Walker's 

 specimen of natural mould of the Ornirhosaurian brain 



