PREFACE 



This volume aims to give an outline of Vertebrate osteology, 

 tracing the skeletal elements from their early appearance to the 

 adult condition, for only by ontogeny can homologies (or their lack) 

 be ascertained in the various groups. Since knowledge of the adult 

 structures of higher Vertebrates is best obtained by comparisons 

 with lower forms, greater stress has been laid on Ichthyopsida and 

 on reptiles than upon birds and mammals, which have been more 

 adequately treated elsewhere than have lower groups. There is 

 also reference to extinct forms, as these frequently throw light 

 upon the Hving species. The work is intentionally descriptive, 

 and no attempts have been made to trace lines of descent, although 

 here and there hints are given of the relations of groups. While 

 teeth are really parts of the skeleton, they are largely ignored here, 

 because of inadequate knowledge on the part of the author and 

 from lack of space. Facts concerning them are readily accessible 

 in the works of Owen, Tomes, Cope, Osborn, Rose and others. 



The writer is conservative in nomenclature, using the terminol- 

 ogy of morphological hterature rather than the names advocated by 

 the worshipper of priority. Acanthias Aniia, and Esox are used all 

 through anatomical hterature and nothing is to be gained by the 

 substitution of Squalus, Amiatus and Lucius. Nor is science bene- 

 fitted by adopting the etymological absurdity Lepisosteus or the 

 typographical error Ambystoma, almost immediately corrected by 

 Agassiz. 



The terminology of the 'BNA' (Basle Nomina Anatomica) 

 has been followed in most cases, but occasionally {e.g., transverse 

 process, obturator foramen) this introduces confusion, while some- 

 times terms must be used for parts lacking in the adult human 

 skeleton, to which the BNA is restricted. In recent years there is 

 a tendency to give new names to parts already well named; the 

 famihar nomenclature is retained here. A few years ago, as a 

 result of misinterpretation of parts, the name paraquadrate was 

 given to the bone here called squamosal, while one author gave the 



