36 
6.—Brancuiart ArcHEs (Fig, 7). 
Ocular Side. 
Basi-branchial I. (B.8r.1).—A triangular bone, with 
its apex wedged in between the upper hypo-hyals (see 
fig. 6). At its base it articulates with basi-branchial IT. 
and with the hypo-branchials of the first arch, but the 
latter articulation is not obvious dorsally, the head of the 
hypo-branchial fitting into a deep lateral socket formed by 
basi-branchials I. and II. According to Cunningham this 
bone is in the Sole completely wedged in between the 
upper hypo-hyals and does not articulate with the first 
branchial arch at all. 
Branchial Arch I.—The epi-branchial (#.Br.') bears 
a prominent tubercle on its anterior surface. The 
pharyngo-branchial (P.Br.') is a slender bone which 
articulates with the skull at the ventro-posterior margin 
of the jugular foramen in the prootic immediately below 
the hyomandibular cup. ‘his somewhat curious connec- 
tion with the skull also exists in the Sole according to 
Cunningham, and in Sebastolobus according to Starks. 
Basi-branchial II. (2.8r.*).—An hour glass shaped 
bone articulating in front with the basi- and hypo- 
branchials of the first arch and behind with basi-branchial 
III. and slightly with the hypo-branchials of its own arch. 
Branchial Arch I]—''he hypo-branchial is wide but 
compressed dorso-ventrally. Where it articulates with 
the second basi-branchial it sends down a prominent spine. 
Another well-marked spine is borne on its anterior edge. 
The cerato-branchial is longitudinally grooved ventrally. 
As in the first arch, the epi-branchial bears a tuberosity, 
but it is much more prominent on this arch. ‘the first 
and last gill rakers are very small. The superior pharyn- 
geal bone of the Plaice in medium-sized fish consists of 
