SEA-FISHERIES LABORATORY. 167 



hyomandibular articulates with the meta-pterygoid. In 

 front of the cartilaginous shaft it simply consists of a thin 

 leafy plate — -a part which is absent in the Sole according 

 to Cunningham. 



Symplectic (>%.)• — Consists of a cartilaginous shaft 

 with a semilunar plate of bone opposed to its anterior 

 edge. Its head forms with the shaft of the hyomandibu- 

 lar the cup for the upper end of the inter-hyal, and also 

 bears a cartilaginous epiphysis. Yentraliy its extremity 

 lies under the quadrate. Its anterior bony margin is 

 attached to the metapterygoid and its upper posterior edge 

 to the pre-operculum. 



Quadrate (Qu.). — A laminate bone bearing posteriorly 

 a strongly calcined ridge and ledge for the pre-operculum. 

 Dorsally it is prolonged into a spine situated in front of 

 the pre-operculum and wedged in between that bone and 

 the symplectic. In front it articulates with the pterygoid, 

 and below its free extremity bears a stout knob with a 

 saddle-shaped articulation for the articular. 



Meta-pterygoid (M.Pt.). — A very thin leafy bone 

 attached to the hyomandibular above, the symplectic 

 behind, the quadrate below, and the meso-pterygoid in 

 front below. 



Meso- or Ento-pterygoid (M_s.Pt.). — Also a thin leafy 

 bone very strongly attached to the pterygoid below. Its 

 lower border in front is more strongly calcified than the 

 rest. 



Pterygoid or Ecto-pterygoid (Pt.)- — A peculiarly 

 shaped bone. It consists of a strongly calcified piece 

 having the shape of an isosceles triangle, the apex point- 

 ing downwards and forwards. When the jaws are shut it 

 is opposed in front to the articular of the mandible. From 

 the posterior angle of its base it sends forwards almost at 

 right-angles a transparent bony rod which is tightly 



