190 Scientific Proceedings, Royal Dublin Society. 



bound to it by a few ligamentous fibres. Viewed from witbin, tbe 

 conoidal part passes ratber abruptly into tbe flattened portion, tbe 

 posterior border of tbe latter being continued some distance down 

 the former, as a prominent ridge ; with tbe inner side of tbe end of 

 this ridge tbe inferior angle of the coracoid articulates ; another 

 ridge, which projects internally, is seen along the anterior border ; 

 this runs into the superior angle of tbe bone above, while below it 

 is lost where it joins the conoidal portion ; near its lower end a 

 thin shelf-like scale of bone diverges from it, and runs obliquely 

 backwards and upwards to the posterior border ; between these two 

 (the ridge and the shelf) is a piece of cartilage, to which tbe ante- 

 rior process of tbe coracoid is fixed, while the upper part of the 

 shelf supports the scapula, which also articulates with the anterior 

 border above it. The outer surface of tbe bone is marked by 

 several grooves and ridges, for the attachment of muscles ; below 

 tbe pointed superior process is a deep, vertical groove, with which 

 the f=upra-clavicle articulates. 



The scapula is a slightly-curved scale of bone, deeply notched 

 below ; the upper and anterior borders articulate with the cla- 

 vicle, and the inferior border on each side of the notch joins tbe 

 coracoid, bounding tbe coraco-scapular fenestra ; the posterior bor- 

 der supports a piece of cartilage, which is embraced by tbe anterior 

 fin-ray, and below and behind tliis tbe first (or anterior), and part 

 of the second, of the three radialia ; these do not come in contact 

 with it, being separated by a strip of cartilage. 



Tbe coracoid consists of a relatively thick, triangular portion 

 above and behind (PI. IX., fig. 24, a), a more elongated triangular 

 portion above and in front, b, and a rod-like piece, which runs 

 downwards from the junction of the other two, c. These are con- 

 nected by intervening thin laminae.^ According -to Parker, these 

 three pieces represent the pree-coracoid, meso-coracoid, and coracoid 

 proper respectively.^ The prse- and meso-coracoid articulate with 

 the scapula ;"the meso-coracoid also with the clavicle ; and the cora- 

 coid proper with tbe clavixile only. The pree-coracoid supports the 

 remaining radialia and the metapterygial basale. 



^ "Periosteal spaces" (Parker, On the Structure and Development of the Shoulder - 

 girdle and Sternum, page 53). 

 ^ Loc. cit. 



