of the Fishery Board for Scotland, 



181 



The general characters at the end of the larval stage of the plaice may- 

 be summed up as follows : — The larvae is large, compared with others 

 originating from pelagic eggs ; the eyes prominent, with a golden lustre 

 (in reflected light) ; embryonic fin broad, with slight black pigment spots 

 on the ventral side ; pectorals large ; and the gut, which at the time of 

 hatching, forms a single lobe, is now divided into two parts, of which the 

 foremost or middle gut is forming a single sling. This is more complete 

 and distinct a few days later. The general pigmentation of the larva is 

 bright yellow, with a few black spots, particularly on the ventral side, 

 Cunningham mentions three rows of pigment along the body ; these are 

 more prominent later. These characters remain nearly unchanged during 

 the first seven days of the post-larval stage ; the chief difference being a 

 rapid growth of the pectorals, and an increase of black pigment, which 

 has now become stellated, particularly in the lateral line of the body ; and 

 the pigmentation in generaLhas spread more to the embryonic fin. 



Sixteenth to Twentieth day after Hatching. 



The active larvae that first appeared at the surface, had in this period 

 begun to quieten, got paler in pigmentation, more inclined to rest with 

 the head downwards, and soni6 of them died. 



Those, again, that had been feeding from the beginning continued to do 

 so ; they were always actively in search for food, which they captured with 

 great voracity. Having discovered a prey, the larvae would approach it 

 slowly to within 1 or T5 mm., when it would contract Jits body laterally, 

 forming part of an 8, and then suddenly throw itself forward, catching 

 the object instantly. Another form of larval mollusk was now commonly 

 seen in the stomachs, a little larger than the one first mentioned (fig. 12). 

 The stomach of fig. 1 shows how greedily this specimen had been feeding 

 on this particular form. The young larvae were often seen to catch various 

 forms of larval crustaceans ; these, however, were not found in the 

 stomachs at this period, so they had not been swallowed. Often I had an 

 opportunity of observing how well armed forms were captured and then 

 again rejected with violence. 



At the end of this period most of those larvae had died, that from the 

 beginning showed the mentioned peculiar symptoms and never took food ; 

 while the mortality amongst the feeding ones w T as very low. 



On the 17th day the average length of three specimens was 7*40 mm., 

 and the average breadth of same 1'44 mm. On the nineteenth day I found 

 one specimen 8 '00 mm. long and 1 52 mm. broad (measured just behind 

 the gut). The difference from the previous period consists chiefly in a 

 further increase in the black stellate pigment, which has now spread more 

 evenly over the body, partly covering the original yellow pigmentation ; 

 the appearance of the larvae now is therefore a faint yellow-greyish colour. 

 Only a few black pigment spots are seen on the dorsal marginal fin, while 

 the ventral part of the body and fin is readily covered with them ; very 

 prominent is a row of black stellate pigment, which extends ventrally 

 from near the snout backwards, along the abdomen and the edge of the 

 marginal fin ; it extends over four-fifths of the length of the whole fish. 

 Anterior to the posterior end of this pigment row is noticed an even 

 development in breadth and thickness of the body, which now appears 

 denser than before ; the posterior portion has remained thin, and a dis- 

 tinct narrow or tapering is therefore now formed on the body at this 

 place. 



The tail has remained unchanged (homocerc), and there is no appear- 

 ance of fin rays. 



