122 
SCANDINAVIAN FISHES. 
ceive the cartilage which connects them with the pos- 
terior rays of the pectoral tins. Another peculiarity 
in the skeleton of the Opah which seems to indicate 
a lower (older) degree of development, appears in 
the structure of the last caudal vertebrae. The last 
of all, as usual, is without any true haemal arch; 
but the three next to it have their haemal arches free 
and not united to the bodies of the vertebrae, and the 
vertebra next in front of these has the haemal arch 
united to its body, but retains the suture between them. 
The penultimate vertebra has both haemapophyses wi- 
dened at the base into a projecting ridge, which runs 
along the lower posterior part of the vertebra on each 
side, and is continued backward across the hypural 
bones, where it is free. We have above remarked a 
ridge corresponding to this in the common Mackerel, 
where it does indeed belong apparently to the hypural 
bones (the last caudal vertebra), though, there too, it 
originates distinctly on the side of the penultimate 
caudal vertebra. Even in the skeleton of the adult 
Mackerel and of the Scad, too, we may trace in the 
last caudal vertebras (as far as the fourth from the 
end) sutures reminding us that the heemapophyses 
were free in the earlier stages of development. Thus 
the skeleton of the Opah, even when the body is 1 1 
dm. in length, explains a, circumstance the elucidation 
of which in the Mackerels must probably be sought 
in the youngest specimens. 
The family Lamprididce thus possesses points of 
resemblance to all the preceding families in the long 
Mackerel-series ■ — to the Bramoids in the high form 
of the body, to the Carangoids in the high supraocci- 
pital crest, to the Scombroids in the large number of 
the vertebrae and to the Xiphioids in the reduction of 
the jaw-teeth and the circular form of the nostrils. 
But in this family we also find anomalopterous cha- 
racters both in the situation of and in the number of 
rays in the ventral tins — the number of the rays 
calling to mind the position of Beryx in the Perch- 
series — as well as in the articulation of the pectoral 
fins. In the formation of the gill-covering apparatus 
it most nearly resembles the Carangoids, though the sub- 
operculum is considerably smaller, and shaped like a 
triangular lamina, which occupies only a tiny part of 
the lower corner of the margin of the gill-opening. 
As our knowledge of the changes of growth in 
the family is so imperfect — we only know that the 
tips of the dorsal and ventral fins become shorter with 
age a - — ■ and especially as the younger stages and the 
supposed larval stage are completely unknown, we have 
no data of sufficient importance to decide the correct 
place of the family. Its whole appearance, however, 
speaks in favour of its retention within the Mackerel- 
series, although the anomalopterous characters just 
mentioned may seem to assign it another place in the 
system. 
Genus LAMPRXS'', 
the only genus within the family, contains only one known species, 
° Cuv., Val., Hist. Nat. Poiss., vol. X, p. 58, tab. 282; cf. also Cuv. (Val.), Regn. Anim. Piastre, Poiss., pi. 61. 
6 Retzius, Vet.-Akarl. Handl. 1799, pt. 2, p. 91. 
