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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 (Sv.).—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. Ventrally its extremity 
lies under the quadrate. Its anterior bony margin is 
attached to the metapterygoid and its upper posterior edge 
to the pre-operctlum. 
Quadrate (Qu.).—A laminate bone bearing posteriorly 
a strongly calcified 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 (J/.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 (J/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 KEcto-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 
