204 
SCANDINAVIAN FISHES. 
of the earlier (lower) stages of development. It also 
seems probable that the palatine and vomerine teeth 
are subject to similar changes and disappear with 
increasing age, for traces of teeth (small and to be 
distinguished only by the touch) occur, in exceptional 
cases, on the vomer in Agonus decagonus. We have, 
however, no further observations on this point. 
The family belongs chiefly to the depths of the 
Arctic seas — one genus, however, Agonopsis , with 
two dorsal fins and both vomerine and palatine teeth, 
belongs to the Antarctic fauna. The true haunt of 
these fishes is apparently the soft, clayey bottom, where 
they feed on all kinds of small animals and often fall 
a prey to the Halibut, being subsequently found in its 
stomach. Some species, however, ascend nearer the 
surface. Jordan and Gilbert estimate the number of 
species at about 16 . In the Scandinavian fauna only 
one genus occurs. 
Genus AGONUS. 
Two dorsal fins. Palatine bones and vomer toothless. Tip of the snout projecting in front of the lower jaw . 
Caudal region elongated and low. 
Thus defined®, the genus Agonus , which was esta- 
blished by Bloch 6 , includes Gill’s genus Podothecus c . 
According to this opinion four species are known, two 
of which belong to the northern parts of the basin of 
the Atlantic and two live in the corresponding parts 
of the Pacific. The first two may be most easily dis- 
tinguished by the different number of pairs of plates 
° Cf. Steindachner, Stzber. Akad. Wiss. Wien, LXXXII (18 
b Blochii Syst. Ichthyol., ed. Schn., p. 104. One year la 
genus Aspidophorus. 
c Proc. Acad. Nat. Sc. Philad. 1861, p. 259. 
(posteriorly forming only one row) from the occiput to 
the caudal fin: 
A : Number of paired aud impaired pla- 
tes in a row on the back from the 
occiput to the caudal fin above 40_.. Agonus decagonus. 
B: Number of paired and unpaired pla- 
tes in a row on the back from the 
occiput to the caudal fin under 37__. Agonus catapliractus. 
, I, p. 255. 
(1802) Lacepede {Hist. Hat. Poiss., tome III, p. 221) entitled this 
