420 
MR. W. K. PARKER ON THE SKELETON 
with the pterygopalatine (fig. 1). Just at its shoulder, below the emerging facial 
nerve (VII.), the extra-hyal sends upwards a free snag. The last extra-branchial 
(ex.br 7 .) sends off no cervicorn processes, except from the transverse bars. It is shorter 
also than the rest. Behind, it joins the extra-pericardial ( pcd.c.) by three bands, the 
lower being the broader (fig. 2), and each of the two fenestrae thus formed is made into a 
U-shaped space by a snag from the extra-pericardial, which also sends forwards, above 
them, a larger free dentate snag; the rest of the pouch is thin, roundly notched, and: 
ends above in another similar process. Below (fig. 2), instead of a small oval fenestra, 
the 7th extra-branchials help the double extra-pericardial to form a large fenestra, 
which becomes elegantly trilobate through the growth of a right and left snag from 
behind. From that fenestra, up to the pair of upper processes, right and left, the two 
extra-pericardials are completely united together, and form a bowl, wdiose cavity is 
pitched forwards and a little upwards. I trust that the reader, with this description 
of the figures here given, will see what the writer sees, and that, seeing, he will agree 
with him that nothing more remarkable, and nothing more exquisite, has been revealed 
by the labour of Anatomists. 
4. Subsidiary cartilages in the mouth and between the mouth and pharynx, 
a. The supra-lingual cartilages. 
Over and between the curious quasi-mandibles that grow upwards from the head of 
the basi-hyal (Plate 18, figs. 6-8, b.liy.) there is a thick pyriform cushion, right and 
left, with its base looking backwards. Between these two cushions, in the margin of 
an elliptical supradingual valley, there is a pair of rows of small, yellow, pointed, 
lanceolate teeth, looking inwards and backwards, a dozen or more in each row 
(Plate 14, fig. 9). There is a groove along the mid-line, between them, and behind this 
the dorsum of the tongue has crescentic cross ridges. Across the arched, broad end of 
the tongue there is a row of cyclodont, beaded, horny teeth, fifteen in all, lessening 
outwards, and with the middle tooth much the larger. These show themselves inside 
the annulus, on the floor of the small oral opening (Plate 8, figs. 10, 11), and are a very 
important part of this suctorial apparatus. But these terminal teeth of the tongue, 
and the radiating teeth of the annular disk, have no counterparts in the Myxinoids 
(Plate 8, figs. 7-9). The two small rows of sharp, supra-lingual teeth have, however, 
very notable counterparts, in the double rows of large teeth, in that lower group (see 
Plate 12, fig. 7 ; and Plate 16, fig. 4). The large complex supra-lingual cartilage 
of the Myxinoids is represented in the Lamprey by a small cartilaginous plate 
(Plate 14, fig. 10, s.l.c.), which is exposed by section in the cushion above the ascending 
lobes of the great basi-hyal ( b.hy.). 
