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24 MR. W. K. PARKER ON THE STRUCTURE AND DEVELOPMENT 
“ stylohyal-” (“‘interhyal ”) of the Teleostei; but it has stopped in its metamorphosis 
at that point where, in the osseous fish, there are two subequal hyoid arches (‘‘ Salmon’s 
Skull,” Third Stage, pl. 2. figs. 6 & 7, hm, c.h). In the Teleostean the ligament would 
be more than halfway down the side of the hyomandibular (three fourths in the 
Salmon, ibid. pl. 6. figs. 1, 2 (hm, st.h). Also in the osseous fish, a nodule of cartilage 
appears in the ligament, like a rudimentary meniscus, which grows into a terete rod and 
ossifies (ibid. st.h). 
The small epihyal (e.hy) is not only attached by its apex to the hyomandibular, but 
also it is closely tied to the front of the first epibranchial at its upper third ; this gill- 
bearing bar is succeeded below by a ceratohyal of equal size (¢.hy); and then there is 
below it a small styloid hypohyal (/.hy), situated on the notched proximal end of the 
first hypobranchial (h.br 1). 
At first sight it would seem as though the hyoid had formed a commisural band 
across behind the mandible (Pl. XLI. fig. 4, 2.dr.1); but that is the belt formed by 
the fusion of the first hypobranchials. The normal direction of the pharyngo-branchials 
(p.br) is backward ; that of the fourth is continuous with the epihyal of the fifth, as 
there is no separate pharyngo-branchial in the last arch. 
The epi- and ceratobranchials are tolerably stout, flat within, grooved outside, and 
strongly tied together by fibrous bands. The arches end below in flat, kidney-shaped, 
adze-shaped, and eyen flabelliform hypobranchials (4.07). That of the last coalesces in 
some degree with its fellow ; and the notched and split plate thus formed reaches by its 
fore horns nearly to the hypobranchial girder of the first arch. 
About twelve or thirteen branchial rays are attached to the hinder edge of each arch 
(see Pl. XLI. fig. 5, d7.7, for those on the hyoid). These are pedate at their distal ends, 
which lie in the outer wall of the sac; and in some of the larger Skates their extremities 
are very large and lobate. 
It is impossible, in the Skate, to prove that the whole of the trabecular growth is not 
axial. Attached to the nasal sac of each side is a large, solid, short, rib-like antorbital 
(a.o), evidently a preoral visceral bar. 
The “labials” are the only “ extraviscerals” found by me in this type. There are 
four on each side ; and the fourth is but slightly connected with the pterygo-quadrate bar 
(Pl. XLII. fig. 4, 7. 4). 
The first pair (/.1) are lanceolate and notched in front; they help the “ cutwater’ 
or “rostrum” very little, being carried away far from the nasal sacs, on which they are 
mounted behind in the Shark (Pl. XX XVII. fig. 2,71). The second labial (/ 2) is in 
front of the nasal opening ; the third (/3) outside; the fourth?! (/ 4) is articulated to the 
second, and lies inside below the rim of the cup and the fore edge of the pterygoid bar. 
? 
1 This fourth labial of the Skate does not answer to the fourth of the Dog-fish, but to the imner of the two 
on the pterygo-quadrate of Scymnus, Squatina, and Centrophorus (Gegenbaur, pls. 11 & 12, Z; the next is 
marked L’, 
