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On the Structure, fyc, of Fossil Reptilia. [June 21, 



by the supra-occipital bone, and that the element which has appeared 

 to be a snpra-occipital is the inter-parietal. Evidence is given of 

 the form of the brain case, which is fonnd to be high and narrow. 

 Details are given of the structure of the squamosal bone, and of its 

 relation to the quadrate and other cranial elements ; and it appears 

 that the squamosal usually embraces the quadrate, so as to extend in 

 front of it, and sometimes to hide it, so that both the quadrate and 

 squamosal sometimes contribute to form the articulation for the 

 lower jaw. Evidence is offered of the sutures which divide the bones 

 of the skull from each other. The sub-nasal element, found in 

 Pareiasaurus, is met with in Dicynodonts, sometimes below the 

 narine, and sometimes within its floor in the position of a turbinal. 

 A new type of quadrate bone, which is regarded as Anomodont, is 

 described, and found to differ from the usual form in being perforated 

 in the antero-posterior direction. A summary of the structure of the 

 skull is illustrated by a restoration showing its sutures. 



Further contributions are made to a knowledge of the vertebral 

 column. The cervical vertebrae are described, the atlas and axis are 

 regarded as anchylosed, and succeeded by an intercentrum which 

 has no neural arch. The cervical ribs are comparatively long, and 

 articulate by a long fork with the neural arch, as well as with the 

 centrum. Further evidence is given of the structure of dorsal 

 vertebras, showing that the rib is attached to a single transverse 

 process of the neural arch. The caudal vertebras of Platypodosaurus, 

 eleven in number as preserved, are described ; and some observations 

 are made on the mode of ossification of the intervertebral substance. 

 Additional materials further elucidate the Anomodont scapular arch, 

 and examples of scapula and coracoid are described; but the only 

 additional pelvic bone described is the pubis of Titanosuehus. 



An account is given of the limb bones, which are elucidated by 

 large bones associated with the skull fragments described by Sir 

 R. Owen as Titanosuehus ferox. They contribute to a knowledge of 

 the femur, humerus, and fibula in that type, and are associated with 

 small bones of the extremities which are probably metacarpals. The 

 ulna is described, which was referred by Sir R. Owen to Pareiasaurus, 

 and evidence is given that it possessed terminal epiphyses of different 

 form to any which are known in fossil reptiles, the proximal epiphysis 

 having much the character of the olecranon of a mammal. A massive 

 Anomodont tibia, also referred by Sir R. Owen to Pareiasaurus, is 

 described, and found to possess a distal talon of mammalian pattern. 



Further observations are made upon the Theriodontia, as restricted 

 to the genus Galesaurus, the skull of which is further elucidated. The 

 author also describes new material, making known the structure of 

 the skull, palate, and scapular arch of Procolophon ; from which it 

 appears that the pre-coracoid is exceptionally w r ell developed, and 



