FLOUNDER-FISHES. 
371 
1. Heterosomata soleina, with the upper jaw most prominent; 
2. „ pleuronectina, with the lower jaw most pro- 
minent, the gape small and oblique, and the 
jaw-teeth considerably reduced on the eye 
side ; 
o. „ liippoglossina , with the lower jaw most pro- 
minent, the gape middle-sized or large, the 
jaw-teeth developed almost as much on the 
eye side as on the blind side, the ventral 
fins one on each side of the ventral margin, 
and the rays of these fins close together at 
the base. 
4. Heterosomata bothina, with the lower jaw most prominent, 
the gape middle-sized or large, the jaw-teeth 
almost equally developed on both sides of the 
body, the ventral fin of the eye side inserted 
just at the ventral ridge, and the rays of the 
ventral fins more or less far apart at the base". 
Subfamily SOLEINA. 
Ethmoid (rostral) cartilage of the snout well- developed, forming the frameivork of a more or less high, hat com- 
pressed elongation of the head in a forward direction. This elongated part of the head generally curves down- 
wards , in a more or less hooked shape , in front of or even under and behind the mouth, which is narrow and 
bent. Jaws (at least the maxillary bones) more or less completely hidden by the lips, and the jaw-teeth, developed 
only on the blind side, where the vent has also taken its 
ing; gill-rakers also iv anting , 
The most conspicuous of the characters given above, 
the projection of the snout in front of the mouth, is 
valid in most cases and, in particular, in the Scandi- 
navian fauna. But the connexion between the forms 
of the family impairs the universal validity of this cha- 
racter, for there are Soles — e. g. Brachirus zebra of 
the Pacific Ocean and the coast of India — in which 
the mouth lies almost exactly at the middle of the tip 
of the head, with the snout projecting extremely little, 
if at all, beyond the tip of the lower jaw. In such 
cases, however, the members of this subfamily may be 
easily recognised by their small eyes and the absence 
of teeth on the jaw-bones of the eye side. 
Just as we have ranged the Flounder-fishes before 
the Codfishes, on account of their far more advanced 
metamorphosis of the Anacanthine type * * 6 , we also give 
the Soles the first place in the Flounder family, because 
the asymmetry has evidently advanced farthest in their 
case. It is also within this subfamily that most of the 
reductions most frequently occur, the pectoral and vent- 
ral fins of one side or of both disappearing, or the eyes 
position. Eyes small or hidden. Pseud obr an chice want- 
on only few and tubercular. 
being hidden by the skin. On the other hand, as we 
have mentioned above, the number of the lateral lines is 
very often increased in these fishes, and numerous feel- 
ers (barbels) are in many cases developed on the head, 
especially on the blind side. The peculiarity so charac- 
teristic of the family of the Flounder-fishes that lies in the 
great length of the dorsal and anal fins (their extension 
over the greater part of the edges of the body), also 
reaches the highest point of its development in the 
Soles. The dorsal fin may not only commence far out 
on the snout, but may even extend downwards round 
the tip of the snout along its ventral margin, which 
in these cases is elongated into a hooked, recurved pro- 
jection of the upper jaw. This projection sometimes 
entirely surrounds the lower jaw c . 
This subfamily contains perhaps half the species 
included in the whole family. In the subfamily too, 
the most numerous and most singular forms belong to 
the tropical seas; but the most delicious and most valu- 
able is a member of the Scandinavian fauna. 
" In this last respect the Mediterranean Citharus linguatula is an exception, having the ventral fin of the eye side inserted just at 
the ventral ridge. But the ventral rays are close together at the base. 
6 The name of Anacanthini was unfortunately applied to an order including the Codfishes and Flounders by Muller (Berl. Abb. 1844), 
Bonaparte having already employed it in 1837 (Syn. Vert. Syst.) for a subfamily of the Bays. 
c As we have not been able to find a trace of pseudobranchiae in Solea or in Cynoglossus, the two extremes of the variations of 
form in the subfamily, we have assumed that this character holds good for the whole subfamily. Kroyer, too {Danin. Fiske, Bd. 2, p. 47G), 
has remarked that Solea vulgaris is without pseudobranchiae. 
