174 
cal limb lying between the nasal chamber and the inter- 
maxillary cartilage, and the horizontal limb passing 
inwards over the top of the cartilage. In front, however, 
the sac les wholly on the top of the cartilage fitting over 
it in a curve like acap. It ends very bluntly in front. 
Ventral nasal sac (7. sac.°).—Its position in the figure 
is somewhat diagrammatic, as it is really situated under 
the nasal chamber and only partly under the dorsal sac. 
It arises from the chamber ventrally from behind, and 
also passes forwards. It is of very irregular shape, and 
gives off externally a small limb which soon terminates. 
Its true extent does not appear in the figure, as it 1s 
situated obliquely dorso-ventrally. It narrows very much 
in front and ends blindly near the outer skin, and between 
it and the intermaxillary cartilage. 
There are no true posterior nares such as Kyle 
describes in one specimen of a Cynoglossus. The nasal 
sacs discharge their contents by the action of the jaw 
apparatus, and apparently fill again with sea water by the 
latter simply passing into the nasal chamber, and thence 
into the sacs, when the animal is swimming. No intrinsic 
muscular action is involved, nor are the nostrils valved. 
The non-fixed parasitic Copepod Bomolochus solee, 
Claus, is not infrequently found in the nasal chamber of 
the Plaice.* 
3.—lTHE EYEs. 
We have only space to consider those features in the 
structure and relations of the eyes and their accessory 
organs which are peculiar to Pleuronectid fishes, and are 
in some way associated with the asymmetry of the head. 
The eyes are situated very near the anterior limit of the 
*For figures, see T. Scott, Eleventh Report Fish. Board Scotland, 
pl. v., figs. 1-10. 
