SKELETON. 



671 



the crests of the iliac bones (c) are bordered 

 with epiphyses ; and this also illustrates a 

 similarity between them. 



Now, having before demonstrated the fact 

 that the sterno-costo-vertebral quantity was 

 a proportional of the dorso- ventral archetype, 

 it must follow that, while a structural homo- 



logy exists between the scapulary or pelvic 

 pairs and the costo-vertebral quantity, so, 

 likewise, should the limbs themselves prove 

 to be the proportionals of the dorso-ventral 

 archetype ; and this we shall next consider. 



Injlg. 490. I represent the dorso-ventral ar- 

 chetype (A), the scapulary pair of members 



Fig. 490. 



Showing the homological relation between the dorso-ventral archetype (A), the scapulaiy 

 organs (B), and the sterno-costo-vertebral quantity (c), and that the difference between 

 these three figures is merely quantitative. 



(u), and the sterno-costo-vertebral quantity 

 (c). What are the corresponding points and 

 the differential characters between these three 

 figures ? Is the difference between them one 

 of quantity merely ? Evidently it is so, and 

 therefore I have marked the corresponding 

 parts of each with the same letter. 



In the dorso-ventral archetype (A), the 

 laminae (4) enclose the neural space (5). In 

 the symmetrical form, constituted of both 

 scapulary limbs (n), the opposed scapulae (4) 

 enclose the space (5) between them. In the 



sterno-costo vertebral form (c), the lamina; 

 (4) enclose the neural space (j). 



In A we find the ventral arches 8 (call 

 these either haemal arches, costae, or what you 

 will) enclosing the ventral space (9). In u 

 the symmetrical humeri (8) enclose the space 

 9. In c the opposite ribs (8) enclose the 

 space 9. In A the neural laminae (4) and the 

 haemal laminae (8) project dorsad and ventrad 

 from the centrum (5). In it the scapulae (4) 

 and the humeri (8) project in the same way 

 from the coracoid bodies (6), which I consider 



