264 MARKETABLE BRITISH MARINE FISHES 



The pigment in these specimens is dark, the black specks are 

 very abundant and evenly distributed, so that no spots or bands 

 are visible ; this distinguishes the turbot from the corresponding 

 stages of the brill. Another remarkable peculiarity is that in 

 the stages from that of 5-42 mm. in length to that in which the 

 transformation is nearly complete the head is provided with a 

 large number of spines, no trace of which remains in the full- 

 grown fish. There is a row of these spines above the eye, a few 

 at the hinder part of the lower jaw, and two strong rows on the 

 gill-cover. The spines are most developed in specimens 10 or 1 1 

 mm. long (|~ inch), and after that gradually disappear. At I3'5 

 mm. in length (just over ^ inch) the right eye is just beginning 

 to show beyond the edge of the head when the specimen is 

 placed on its right side. In the largest specimen, 16 mm. long, 

 (TTTO- inch) half of the right eye is visible from the left side. 



These specimens were captured off the Horn Reef light 

 vessel, near the coast of Denmark, on the Great Fisher Bank, and 

 off the north-west corner of the Dogger. It is a curious fact that 

 while they were brought to Grimsby from distances between 

 60 and 220 miles in the North Sea, numbers of specimens in 

 the older stages come, of their own accord, almost to the doors 

 of the Plymouth Laboratory. They are brought in with the 

 flood tide to Sutton Pool, and, swimming as they do at the very- 

 surface of the water, are dipped up by boys in rusty tins 

 and brought to the Laboratory for sale. The sizes of such 

 specimens are commonly from 15 to 25 mm. ( T 6 F to I inch), but 

 recently a series of the younger stages described by Mr. Holt were 

 obtained in the same manner. Fig. 124 represents a specimen 

 inch long. There are several interesting and remarkable 

 features about these young forms. The transition stages of other 

 flat-fishes have been obtained near the bottom ; those of the 

 flounder, plaice, and dab, have no air-bladder, and when their 

 habits are noticed it is seen that they swim up from the bottom 

 by active exertion of the fins and fall when not moving. The 

 sole has an air-bladder in the transformation period, but has not 

 been taken at the surface in the open water. But the youn^ 

 turbot float, or soar, in the water with no exertion at all, using 

 their fins gently now and then to move deliberately and rather 

 slowly in one direction or another. They can also in a tank lie 

 at the bottom, and although found at the surface, seem to be able 



