Greensand Pterodactyles 



59 



remains of flying saurians, or pterodactyles, from the Cam- 

 bridge Greensand, of which large series are preserved in both 

 the Sedgwick and the British Museums. Some of these 

 bones indicate reptiles of gigantic size. Unfortunately they 

 are all, or nearly all, in a more or less fragmentary condition, 

 which renders the interpretation of their affinities a matter 

 of extreme difficulty and uncertainty. Under these circum- 

 stances they are, with one exception, referred to a single 

 generic type, although it is quite probable that, if their con- 

 dition were more satisfactory, several such groups might be 

 indicated. One of the most remarkable of these bones appears 

 to indicate part of the upper jaw of a toothless pterodactyle 

 allied to Pteranodon of the Upper Cretaceous strata of the 

 United States. The form to which it belonged has been 

 named Omitkostoma 1 , but no specific title has been assigned. 

 If the type specimen be really what it is considered to repre- 

 sent the name Ornithostoma seeleyi would be appropriate. 



The numerous other forms of pterodactyles from the Cam- 

 bridge Greensand, here classed in the genus Ornithochirus^ 

 (inclusive of Cimoliornis, Coloborhynchus, and Criorhynchus), 

 have been described by Prof. Seeley 3 . Taking into considera- 

 tion firstly those represented in the collection of the British 

 Museum, we find in 0. sedgwicki a large species allied to 

 0. cuvieri of the Chalk (which may itself also occur in the 

 Cambridge Greensand), but with a deeper and blunter muzzle 

 and some difference in the form and position of the sockets of 

 the teeth. In 0. fittoni the beak is much less deep, and 

 the sockets of the teeth are larger and separated by wider 

 intervals. On the other hand, 0. (Criorhynchus) simus is 

 characterized by the great depth and bluntness of the muzzle, 

 as well as by its huge bodily size. Of species unrepresented 

 in the British Museum 0. denticulatus is of the approximate 

 size of 0. fittoni, but has smaller and more numerous teeth ; 



1 See Seeley, Quart. Journ. Geol Soc. xxxn. 499 (1870). 



2 See Cat. Foss. Rept. Brit. Mus. i. 10. 



3 Ornithosauria, Cambridge, 1870. 



