342 THE FLOUNDER FAMILY. 



vent and the tail. A little pigment occurs on the under 

 surface of the belly, and behind the vent is an indication of an 

 anterior pigment-bar. The coloration is alike on both sides of 

 the fish, as usual in such pelagic forms. 



The eyes are of considerable size, and are lateral in position, 

 that is, one occurs on each side of the body. The animal is as 

 yet too young for any change to be visible in the left eye. 

 The vent is situated a little in advance of the median line of 

 the body. 



The marginal fin is somewhat injured, but it seems to have 

 been of moderate depth, and traces of true rays appear both 

 dorsally and ventrally, though the free edge is wholly embryonic. 

 The tail shows dorsally the terminal bend of the notochord 

 (early backbone), but it does not taper much, and the embryonic 

 fin forms an apparently shorter lobe than in the flat fishes 

 hitherto examined. Moreover, on comparison with young turbot 

 at the same stage of development, the difference in size is 

 marked. Before the turbot reaches the length of the present 

 form (brill) it has lost the characters still found in the latter, 

 e.g. the embryonic lobe at the upper region of the tail, which 

 has its permanent inferior part furnished with much more 

 developed true rays than in the young fish from Smith Bank. 



The brill has an egg considerably larger than that of the 

 turbot, so that the larval fish starts life in advance of the turbot 

 in size. Consequently the post-larval turbot at a given size is 

 an older fish than the brill, and its organs are further advanced. 



In what appears to be a brill of 11 mm. (Plate XIII, fig. 10), 

 procured at the surface on the 23rd June, 12 — 14 miles from 

 the coast of Aberdeen, further progi-ess has been made. In life 

 it much resembled a young flounder in colour and was difficult 

 to detect; indeed the attendant lost it in the jar, and only 

 recovered it after death had made the tissues more opaque. 

 When it reached the Marine Laboratory it was more or less in 

 the latter condition, with a slightly yellowish hue of the body, 

 which, with the head, wa.s dotted all over with large and small 

 black chromatophores. The dorsal fin, which had true rays, 

 had six black touches, and portions of two were present in 

 the anal, which with the abdomen had been injured. The 



