556 Mr. E. W. Hooley on the 



Os innominatum. 



Examples of the ossa innominata are arranged on tablet 

 J. b. 10, and numbered 1-9. In those specimens, where tlie 

 acetabulum is preserved, it is imperforate, and the surrounding 

 bones anchylosed and apparently near to Oniithostoma 

 (^Pteranodon) ingens, where the bones are conjoined and the 

 acetabulum shallow and imperforate. 



Femur. 



There is only one perfect specimen of the femur, the other 

 exauiples are fragmeuts. Tliey may be divided into two 

 groups : — 



(1) Neck and head oblique to the shaft. Great trochanter 



weak. Shaft straight and large. Example : 

 J. c. 2, 11, 20. 



(2) Neck and head very oblique. Great trochanter 



robust. Shaft straight and small. Example : 

 J. b. 11, 1. 



Both are illustrated in ' Ornithosauria,' pi. viii. figs, .5, 6, 

 7, and 8. In neither group are the head and neck as 

 terminal as in Ornithodesmus latidens. Tlie shaft is not 

 curved as much as in the American forms; otherwise the 

 description by Professor Williston * of the femur of Oniitho- 

 stoma (Ptei'anodon) ingens is near to Group 1 and also to 

 Nijctosaurus [Nyctoductylus) f. To which genus the speci- 

 mens included in Group 2 belong must remain an open 

 question. 



In concluding our examination of the Cambridge Green- 

 sand material in the Cambridge Museum, Cambridge, we find 

 that the jaws divide into five genera — Ornithocheirus, Lon- 

 chodectes, Amhlydectes, Crwrhgnchus, and Ornitliostoma. 



On the evidence of the premaxillse Ornithodesmus is 

 entirely separated from either genera of the Cambridge 

 Greensand, but the fragments of the humeri and ulnae of 

 Group A must undoubtedly be incorporated into the same 

 family, and there is nothing to prove that the humeri and 

 uhiie included in Group A should be assigned to reptiles 

 possessing premaxillje typical of one of the five genera. 

 Neither can any of the other bones of the axial skeleton be 



* S. W. Williston, Kansas Univ. Quart. 1893-4, ii. p. 80. 



t Id. Field Col. Mus. Pub. 78, geo. ser. 1003, vol. ii. no. 3, \\ 150. 



