48 THE STRUCTUEE OF MAN 



it, must not be confounded with the above-described skeletal 

 structures, which are entirely incorporated into the manubrium. 

 These "ossa suprasternalia " (o.s., Fig. 30) may be derivatives of 

 the episternal apparatus, as Gegenbaur has for years insisted, and 

 probably of the central portion of the episternum. The lateral 

 portions of this structure are usually homologised with the inter- 

 articular cartilages that lie between the sternum and the ventral 

 extremities of the clavicles (e.s., Fig. 30). [There is, however, 



r . l". 



FIG. 30. EPISTERNAL VESTIGES IN MAN. 



e.s,, " episternum " (sterno-clavicular cartilage); o.s., ossa suprasternalia ; cL, clavicle, 

 sawn through; I'., inter-clavicular ligament; I"., costo-clavicular ligament; m.s., 

 manubrium sterni ; st., sternum ; r.c., first rib. 



still considerable uncertainty about this ; especially as Carwardine 

 has recently shown x that the ligaments in which the " ossa supra- 

 sternalia " lie embedded when free, may or may not be continuous 

 with an " inter -clavicular ligament" which, by its T-shaped 

 character and detailed relationships, may suggest the inter-clavicle 

 (episternum) of Monotremes and Eeptiles.] 



THE SKULL 



In all Vertebrates the skull may be divided into two 

 principal portions, the cranial and the facial. The cranial 

 portion, or brain case, encloses the anterior part of the central 

 nervous system, and is intimately associated with the higher 



1 Jour. Anat. and Phys., vol. xxvii. p. 232. 



