Io8 ALUS. [Vol. XVIII. 



of the suprascapular, and almost reaches the outer edge of that 

 dorsal ridge of the skull that separates the temporal and supra- 

 temporal grooves. The bone is thus limited, in position, to that 

 part of the dorsal surface of the head that lies directly superficial 

 to, or superficial and posterior to, the hind end of the temporal 

 groove. The shank and lateral arm of the bone are traversed, their 

 full length, by the main infraorbital lateral canal ; the mesial arm 

 being traversed by the supratemporal branch of the same canal. 

 The bone is developed in relation to the canals by which it is 

 traversed, and is imperfectly or incompletely formed, the openings 

 on its dorsal surface being more numerous than the primary tubes 

 that lead outward from the enclosed canals. 



The Suprascapular (SS, Fig. 5) is an irregular bone lying 

 immediately behind and partly internal to the extrascapular. It 

 consists of a relatively large, flat and stout, scale-like body, a 

 strong antero-mesial process, and a strong inferior process, or 

 pedicle. It lies, in general direction, obliquely to the body, extend- 

 ing forward, upward and mesially from its hind end. Its hind 

 end overlaps the supraclavicular, while its anterior end is over- 

 lapped by the shank and mesial arm of the extrascapular. 



The body of the bone lies in the dermal tissues superficial to 

 the trunk muscles. Posteriorly it ends in a delicate scale-like edge, 

 and anteriorly there arise from it two splint-like processes which 

 project forward and slightly downward in the temporal groove. 

 These two processes are often fused for a considerable distance 

 from their bases, a single process with two pointed ends being 

 thus formed. These ends may extend forward to the point where 

 the temporal groove is crossed by the ledge that separates it into 

 its two portions or levels, but they do not usually quite reach that 

 point. The posterior two thirds or three quarters of the body 

 of the bone is traversed by the posttemporal part of the main 

 infraorbital lateral canal. 



The antero-mesial process of the bone arises from the ventral 

 surface of the mesial edge of the anterior half of the body of the 

 bone, and runs horizontally forward and mesially across the dorso- 

 posterior process of the exoccipitale, its anterior end almost reach- 

 ing the base of the spina occipitalis. This process of the bone thus 

 lies partly superficial to the temporal groove, near its hind end. 



