622 
SCANDINAVIAN FISHES. 
composite dental growths, one or two in each jaw, 
which project like a beak beyond the lips — hence the 
name of les Gymnodontes , from yvurog, naked and bd'ovg , 
tooth. Of these families the latter is distinctly more 
perfectly Plectognate in its characters. At the present 
time we generally follow Bonaparte" and divide these 
fishes into four families, two within each of the Cu- 
vierian families b . Only two species, each representing 
a distinct family, have been found within the limits 
of the Scandinavian fauna. 
Fam. 0 R T H A G 0 R I S 0 I S) M. 
Gymnodonts with stunted trunk , body compressed laterally { round or elliptical) and not distensive, and- contiguous 
vertical fins. Dental disks of the jaws undivided. Pseudobranchice large. Air-bladder 0 , pelvic bones , 
and ventral fins wanting. 
With an appearance as though they were of the 
normal piscine form but with truncate tail, these Lagg- 
bukar {Tun-bellies) as Retzius called them together 
After Wellenberg. 
with the rest of the Gymnodonts — deservedly excite 
attention even by their external characters. In form 
and appearance they remind us somewhat of the Opah; 
but merely a casual examination is enough to show 
that they are of an entirely different type. They really 
rank among the most singular piscine forms. The 
stunted appearance of the body depends, it is true, on 
the comparatively small number of the vertebrae (16 
or 17); but this number may be still smaller in the 
Coffer-fishes. The short form of the body is really 
caused by its depth posteriorly, this being due to a 
prominent development of the upper and lower arches 
of the vertebrae, with their spinous processes, in the 
caudal part of the body, and of the interneural spines 
of the dorsal fin and the in ter haemal spines of the anal 
fin (fig. 153). This deviation from the other Plecto- 
gnates is connected with an extremely unusual course 
of development. 
In the middle of the last century KolreuterC gave 
an excellent description and a figure of no small merit, 
considering the period of its execution, of a fish 16 
mm. long and 19 1 / 2 mm. deep, “which at a casual 
glance might easily be taken for a head cut off from 
the trunk, and nothing more.” Closer examination 
soon showed, however, that this specimen was a young 
form of Orthagoriscus ( Tet-rodon ) mola, as Linnaeus e 
interpreted this find. But the most singular circum- 
stance was that it had no caudal fin whatever. In 
another specimen, 40V 2 mm. long and 49 1 / 2 mm. deep, 
on the other hand, Kolreuter found a distinct, cre- 
nulated caudal lobe along the hind margin of the fish, 
uniting the dorsal fin to the anal. Since that time 
these small fishes have been met with on numerous 
“ Catalogo metodico dei pesci europei , p. 87. 
b Bleeker ( Atlas Ichthyologique, tome V) divided the Plectognates into three orders and these again into 6 families corresponding to 
Gunther’s subfamilies: Ostraciontina ; Triacanthina , Balistina; Triodontina , Tetrodontina , Molina. 
c Costa ( Fn . d. Regn. di Napoli , tav. 63 e 64) describes and figures a rudimentary air-bladder in Orthagoriscus mola. 
d Nov. Comment. Acad. Sc. Petrop., vol. X (1766), p. 337, tab. VIII, figs. 2 and 3. Mola aculeata , limbo abdominis producto, 
attenuate , carnoso. 
e Syst. nat., ed. XII, tom. 1, part. 2, Add. (in fine). 
