THE FLOUNDER FAMILY. 391 



and young turbot in the apparatus at Dunbar. The breast- 

 fins (pectorals) vibrate like those of the sea-horse {Hippocampus), 

 a resemblance the more appropriate from the dermal process 

 on the head, and the tail appears to move as rapidly. Like 

 other pleuronectids in still water the larval soles chiefly kept to 

 the bottom of the vessel at this stage, swimming obliquely with 

 the head directed downward, as if boring into the bottom 

 or sides. Occasionally, however, a swift dart was made right 

 across the vessel, or a shorter one as if capturing prey. The 

 mandible (lower jaw) moves regularly as in respiration. The 

 yolk has now diminished to a small mass anteriorly, with 

 groups of oil-globules crowded together, while the posterior 

 region of the abdomen is occupied by the viscera. This 

 forward progress of the yolk is interesting, for while different 

 conditions occur in the series, one of the most common is 

 the absorption of the anterior region, and the consequent 

 presence of the diminished yolk posteriorly. Another feature 

 of note is the occurrence of a prominent fold along the ventral 

 margin of the abdomen. The pigment seems in some to be 

 more decidedly ochreous, and to have less of the dull yellowish- 

 white (like Tripoli powder) so characteristic of the early 

 condition. Along the dorsal margin of the muscle-plates are 

 a series of pigment-patches, which appear to be more numerous 

 than in the example of the post-larval stage, but variations may 

 occur in this respect. 



As the larval sole gets a little older, for instance two days 

 subsequent to the preceding stage, the pigment becomes more 

 distinctly ochreous, and the yellow chromatophores along the 

 dorsal edge of the muscle-plates show signs of increase. More- 

 over, the pigment-spot on the occiput, so characteristic of the 

 subsequent stage, is outlined. Eight distinct patches occur 

 behind the former, one of the posterior (seventh from the 

 occipital) being larger, and almost meeting that from the 

 inferior edge. The character of the head is as peculiar as in 

 the previous stage, so that the active little fish can readily see 

 ahead. The yolk has now shrunk to a small mass under the 

 liver, in front of the gall-bladder, and is not easily distinguished. 

 The change from the buff or stone-coloured, or even the dull 



