ONTOGENY AND PHYLOGENY OF THE STERNUM 



57 



cellular element extending across the middle line, and could 

 compare this with equally well-drawn stages from the material 

 of Whitehead and Waddell, an unprejudiced worker, from a 

 study of the figures, supplemented by his own observations, 

 might bring the whole tangled mass into harmony. As it is, the 

 present author has but little to start with except the verbal 

 statements of the opposing theorists. 



Table 1 gives at a glance the position of several of the leading 

 workers in their attitude toward the problem. 



TABLE 1 



Ruge, G. ('80) 



Paterson ('00) 

 Paterson ('02) 

 Paterson ('04) 



Kravetz ('95) 



Mueller ('06) 



Parker ('91) 



Whitehead-Wad- 

 dell ('11) 



Rathke ('48) 



OKIGIN OF STERNUM 



Ventral ends of 

 ribs 



Shoulder girdle 



Two longitudinal 

 bars 



Ventral ends of 

 ribs 



Coracoidal and 

 costal 



'In situ' 



Two longitudinal 

 bars 



FORMS STUDIED 



Man 



Rat, rabbit, man, 

 dogfish 



Pig 



Man 



Hexanchus Ap- 

 teryx 



Pig, cat, man 



Batrachia, chick, 

 pig 



HOMOLOGY 

 OP PRESTERNUM 



Middle part shark 

 girdle 



No morphological 

 importance 



Episternum 



Omo-sternum in 

 shark; omo-ster- 

 num in am- 

 phibia 



Episternum; pro- 

 sternum 



