464 STERNUM. 



xiphosternum have the same origin as the main body of the sternum 

 (Ruge, No. 438). _ 



In the Amphibia there is no structure which admits from its 

 mode of development of a complete comparison with the sternum 

 of the Amniota ; and it must for this reason be considered doubtful 

 whether the median structure placed behind the coracoids in the 

 Anura, which is usually known as the sternum, is really homologous 

 with the sternum of the Amniota\ 



The remaining Ichthyopsida are undoubtedly not provided with a 

 sternum. 



Bibliography of Ribs and Sternum. 



(430) C. Claus. "Beitrage z. vergleich. Osteol. d. Vertebraten. I. Rippen u. 

 unteres Bogensystem." Sitz. d. kaiserl. Akad. Wiss. Wien, Vol. lxxiv. 1876. 



(431) A. E. Fick. " Zur Entwicklungsgeschichte d. Rippen und Querfortsatze." 

 Archiv f. Anat. und Physiol. 1879. 



(432) C. Gegenbaur. " Zur Entwick. d. Wirbelsaule des Lepidosteus mit vergleich. 

 anat. Bemerk." Jenaische Zeit. , Vol. iii. 1867. 



(433) A. Gotte. "Beitrage z. vergleich. Morphol. d. Skeletsystems d. Wirbel- 

 thiere Brustbein u. Schultergurtel. " Archiv f. mikr. Anat., Vol. xiv. 1877. 



(434) C. Hasse u. G. Born. " Bemerkungen iib. d. Morphologie d. Rippen." 

 Zoologischer Anzeiger, 1879. 



{435) C. K. Hoffmann. " Beitrage z. vergl. Anat. d. Wirbelthiere. " Niederldnd. 

 Archiv Zool., Vol. iv. 1878. 



(436) W. K. Parker. "A monograph on the structure and development of the 

 shoulder-girdle and sternum." Ray Soc. 1867. 



(437) H. Rathke. Ueb. d. Bauu. d. Entwicklung d. Brustbeins d. Saurier. 1853. 



(438) G. Ruge. "Untersuch. iib. Entwick. am Brustbeine d. Menschen." Mor- 

 phol. Jahrbuch., Vol. vi, 1880. 



1 The so-called sternum of the Amphibia develops in proximity with certain 

 rudimentary abdominal ribs, and Ruge has with some force urged (against Gotte) that 

 it may be for this reason a rudimentary structure of the same nature as the sternum 

 of the higher types. 



