408 
SCANDINAVIAN FISHES. 
we further compare this table with the table given 
above (p. 401) of the changes of growth in the Plaice 
and the Flounder, we easily find that, in all those re- 
lations in which the changes of growth of these two 
species show a distinct and common direction of de- 
velopment, the juvenile stages are represented either 
by PL liman da, PL glacialis or PL cicatricosas, or by 
two of these forms in common. This series of forms, 
which, as far as we know at present, culminates in the 
Plaice and the Flounder, thus seems to have originally 
started either from one of these three forms or in close 
systematic proximity to them. 
Subfamily H I P P 0 G L 0 S S I N A. 
Snout not elongated , the lower jaw most prominent. Mouth middle-sized or large and only slightly oblique; jaw- 
teeth almost as well-developed on the eye side as on the blind side. Ventral fins one on each side of the ventral 
margin, and their rays close together at the base. Eyes large or at least middle-sized. 
Pseud nbranchire and, in most cases, gill-rakers well-developed. 
This subfamily derives its name from the well- 
known Halibut, Hippoglossus , and contains about 30 
described species, distributed among 5 or, if we please, 
as many as 9, distinct genera: ( Psettodes + Athe- 
i ■ estes ) , ( Tlippoglossus + PI a tysomati ch thys) , (Pa rail ch thys 
+ Pseudo rhomb us), ( Drepanopsetta + Psettichthys ) and 
Tephritis. The most numerous and the largest species 
live in the North, but several belong to the tropical 
seas, to West Indian, East Indian, Chinese and Japa- 
nese waters. 
The peculiarity which we have remarked above as 
characteristic of the juvenile stages of the true Floun- 
ders (subg. Platessa, auctt.), the pointed jaw-teeth set 
in several rows, in this subfamily as well as in the 
following one, is the rule even in adult specimens. 
The principal characteristic of these two subfamilies 
lies, however, in the fact that the asymmetry of the 
head has only slightly affected the structure of the 
jaws. Thus, the jaw-teeth of the eye side may be al- 
most or even quite as well-developed as those of the 
blind side. On the other hand, the subfamily of the 
Halibuts comes nearer the preceding Flatfishes in the 
position of the ventral fins and the form of the pelvic 
bones. In essential respects at least, the ventral fins are 
symmetrical in position, one on each side of the ventral 
margin; and the pelvic bones are of the normal Hetero- 
somatous form, a narrow triangle, and hang, closely 
united to each other, backwards and downwards or 
straight downwards (centrally) from the inner side of 
the coalescent clavicular bones, being suspended within 
and somewhat above the lower end of the coracoid 
bones. To the outer side of the short base of the 
triangle are attached, as usual, the rays of the ventral 
fins, with their roots (articulations) close to each other. 
Another character that seems to be common to the 
members of this subfamily lies in the circumstance that 
all the caudal vertebra} are entirely without transverse 
processes or possess only very slight traces thereof. 
The Scandinavian fauna contains only two, or, if 
we choose, three, genera of this subfamily, each genus, 
in the latter case, with only one species. 
A: Jaw-teeth, in the upper 
jaw at least, set in two or 
more rows. Scales cycloid. 
a : Lower pharyngeal teeth 
set in two rows. Lateral 
line sharply arcuate in 
front, above the pec- 
toral fins Hippoglossus vulgaris. 
I : Lower pharyngeal teeth 
set in a single row. 
Lateral line evenly 
sloping in front Platysomatichthys hippoglossoides. 
B: Jaw-teeth set in a single 
row®. Scales ctenoid. 
Lower pharyngeal teeth 
set in two irregular rows. 
Lateral line evenly sloping JDrepanopsetta platessoides. 
Does not apply to all exotic species of the genus. 
