Nos. IAND2.] ANATOMY OF SCOMBER SCOMBER. 143 



concavity in the remainder of the interspace. The general appear- 

 ance of the cartilage here, when cut and examined under low 

 powers, was exactly the same as that found in sections of the 

 cartilaginous basal line of lan'se of Amia at the points where, later, 

 the line separates into its several parts. 



Goronowitsch (No. 32, pp. 32-34) considers the anterior, or 

 postorbital articular head of the hyomandibular of teleosts, as the 

 primary dorsal end of the element, the posterior, squamosal head 

 being of secondary and later origin. A lamellar wing is said by 

 him to be developed along the posterior edge of the axial part of 

 the hyomandibular, very probably as a surface of insertion for the 

 Mm. operculare, and the dorsal edge of this wing is said to acquire 

 articular relations with the squamosal. This, and other consider- 

 ations, are then said by him to indicate that the cranio-hyoid artic- 

 ulation has, in the higher fishes, first shifted forward, from a pos- 

 terior position, onto the postorbital process, and then reacquired 

 a secondary, posterior, squamosal articulation in the manner indi- 

 cated. Amia and Scomber certainly do not support this proposi- 

 tion ; for in both these fishes the squamosal part of the articular 

 end of the hyomandibular seems to belong to the axial part of the 

 element fully as much as the postorbital articular end, and in 

 neither fish does the hind edge of the hyomandibular give insertion 

 to the Mm. operculares, those muscles arising directly from the 

 lateral surface of the skull. Why a special plate should be 

 especially developed on the hyomandibular to give to these muscles 

 the disadvantageous point of origin they would necessarily have 

 upon that bone, is not easily imagined ; more especially as, in their 

 apparent derivation from the adductor hyomandibularis, they had 

 from the start a more advantageous position. 



The Symplectic {SY) is a long, narrow, tapering bone 

 directed downward and forward from the interspace of cartilage 

 that unites it with and separates it from the hyomandibular. The 

 dorsal part of the bone lies between a long, dorso-posterior proc- 

 ess of the quadrate and a narrow line of cartilage that edges the 

 ventral part of the hind edge of the metapterygoid, being separated 

 from the process of the quadrate by a narrow space, but lying 

 directly against the strip of cartilage. The ventral part of the 

 bone lies in a deep groove on the inner surface of the quadrate, 



