Geological Society. 151 



termuscular crest or keel, it could not have been a strictly terrestrial 

 bird, though these characters do not prove that it was a bird of 

 night, as they occur in the Penguins or other Brachyptera, which 

 have need of muscular forces to work their wings as paddles under 

 water. In the present fossil, however, from the lateral extent 

 and convexity of the sternal plate, the presence and course of 

 the secondary intermuscular ridges, the commencement of the keel 

 a little way behind the anterior margin of the sternum, Mr. Owen 

 says there is no affinity with the brachypterous family. The cora- 

 coid bones or posterior clavicles, he also shows are less available in 

 determining the habits of the Ornitholite, as they relate much more 

 closely to the respiratory actions than to the movements of the 

 wings, and are strongly developed even in the Apteryx. There re- 

 mained consequently for comparison the ordinary birds of flight; 

 and of these, the native species, which resemble the fossil in size, 

 first claimed Mr. Owen's attention. Though the sternum is not 

 complete, yet sufficient remains to have enabled him to set aside the 

 Gallinaceous, and those Grallatorial and Passerine birds which have 

 deeply incised sternums, and to restrict the field of comparison to 

 such species as have the sternum either entire, or with shallow pos- 

 terior emarginations. After a rigid comparison of the minor struc- 

 tural details and pursuing it from the sea gulls and other aquatic 

 birds upwards through the Grallatorial and Passerine orders, omitting 

 few British species, and no genus, he at length found the greatest 

 number of correspondences in the skeleton of the accipitrine spe- 

 cies. The resemblance, however, was not sufficiently close to ad- 

 mit of the fossil being referred to any native genus of Raptores : the 

 breadth of the proximal end of the coracoid removes it from the 

 owls (Strigidte), the shaft of the same bone is too slender for the 

 Falconidae ; and the femur and tibia are relatively^weaker than in 

 many of the British Hawks or Buzzards. It is with the Vultures 

 that Mr. Owen has found the closest agreement ; but he says the 

 fossil indicates a smaller species than any known to exist in the 

 present day, and is probably a distinct subgenus. 



The professed ornithologist, Mr. Owen remarks, may receive 

 with reasonable hesitation a determination of family affinities arrived 

 at, in the absence of the usual characters deduced from the beak 

 and feet ; but in the course of a long series of close comparisons, he 

 says, he has met with so many more characters, both appreciable and 

 available in the present problem, than he anticipated, that he confi- 

 dently expects, in the event of the mandibles, the bones of the feet, 

 or the entire sternum of the bird in question being found, they will 

 establish his present conclusion, that the Sheppey ornitholite is re- 

 ferrible to a member of the group of Accipitrine Scavengers, so 

 abundant in the warmer latitudes of the present world. 



The Ornitholite in Mr. Bowerbank's museum consists of ten sa- 

 cral vertebrae anchylosed together, as is usual in birds with a con- 

 tinuous keel-like spinal ridge. Four of the vertebrae are analogous 

 to the lumbar vertebrae in the mammalia, and they are succeeded by 

 five others, in which, as in the Vultures, the inferior transverse pro- 



