124 THE SKULL [chap. 



f and by its upper end firmly ankylosed with the surround- 

 ing bones. It can be seen much more distinctly in some 

 dogs' skulls than others, and is more conspicuously de- 

 veloped in some other Mammals. This I have calledj^- 

 paiwhyal, as it is always in relation with the hinder edge 

 of the tympanic bone, generally more or less surrounded by 

 it, and it extends upwards, embedded in, and afterwards 

 . ankylosed with, the periotic, to the hinder wall of the 

 tympanic cavity. Its lower end is truncated and con- 

 tinued into a band of cartilage, which connects it with 

 the proximal end of the bone which has been generally 

 j recognised as the uppermost of the series forming the 

 I anterior hyoidean arch, the stylohyal (s/i). The two suc- 

 1 ceeding bones {ep and ch) are named by Professor Owen 



(respectively epihyal and ceratohyal. All three are elon- 

 gated, compressed, slightly curved or twisted on them- 

 selves, tipped at each end with cartilage, and connected 

 with each other by synovial joints. The stylohyal and 

 epihyal are nearly equal in length, the ceratohyal shorter 

 ( and stouter. 



The basihyal (bh) is a transversely-extended, flattened bar, 



! with its extremities rather upturned and thickened. The 



posterior cornu (t/i) consists of a single, nearly straight, 



I compressed bone, the t/iyro/iyal, articulated inferiorly with 



the outer end of the basihyal, just below the attach- 



\ ment of the ceratohyal, and truncated at its superior ex- 



, tremity, to which the thyroid cartilage of the larynx is 



suspended. 



Development of the Skull. — For a detailed and beautifully 

 illustrated account of the early development of the Mam- 

 malian skull, I must refer to Professor Parker's monograph 

 f* On the Structure and Development of the Skull in the 



