of the Fishery Board for Scotland. 



2*73 



During the post-larval period the pigment on the two sides of the body 

 remains practically identical. It is only in the larger specimens, e.g. 

 38mm., that it is possible to detect a lighter shade of pigment on the left 

 side than on the right. 



With the transformation, however, a very marked difference is noted 

 (Fig. 13). The fish itself becomes more opaque, and its upper surface 

 (the previous right side), shows a large quantity of pigment. Posterior 

 to the anus there are on the upper surface seven broad patches across 

 the median line of the body ; on the dorsal fin there are five broad patches 

 with intermediate smaller patches, and on the ventral fin three broad 

 patches with smaller intermediate groups. The under or blind side, 

 however, retains the post-larval pigmentation ; in this case it resembled 

 that found in the post-larva measuring 38mm. (Fig. 2). 



Holt and Byrne draw attention to the presence of spines on the 

 operculum of the post-larvse. I have found this spinous armature in the 

 example measuring 12 , 5mm. (Fig. 2). In the preceding specimen, 

 5 '2mm. (Fig. 1), it was not made out. It was found in all the succeeding 

 post-larval witches, and the spines were equally developed on both sides 

 of the body. The sketches indicate with approximate accuracy the 

 number and arrangement of them. 



In the metamorphosed example, 44mm. long (Fig. 13), teeth were found 

 on the operculum. Two large teeth projected from the posterior part of 

 the operculum, and dorsal to these three were two (or three) other similar 

 teeth. They were equally developed on both sides of the fish. 



No spines were made out on the operculum of either side in the young 

 witch measuring 59mm. in length. 



Small teeth (in the jaws) were made out in the smallest member of 

 the series, and they were present in all the other post-larval stages. They 

 are not numerous. Teeth were not seen in the smaller bottom form. 



LITERATURE. 



Cunningham. — "The Eggs and Larvse of Teleosteans," Trans. Boy. Soc, 



Edinburgh, vol. xxxiii., Pt. L, p. 97 (Plates I. to VII.). 1887. 

 Cunningham. — " Marketable Marine Fishes." London, 1896. 

 Holt. — " On the Eggs, Larval and Post-larval Stages of Teleosteans," Sc. Trans. 



Boy. Dublin Society, ser. 2, iv., p. 455, Plates I. to XV. 1893. 

 Holt and Byrne. — "On a Young Stage of the White Sole {Pleuronectes 



cynoglossus)" Report on the Sea and Inland Fisheries of Ireland for 1901, 



Pt. II., p. 67, Plate III. Dublin, 1903. 

 Kyle. — "Halibut (Hippoglossus vulgaris, Flera.) or Pole-Dab {Pleuronectes 



cynoglossus," Journal of the Marine Biological Association, vol. vi., No. 4., 



Dec. 1903, p. 618, 1 plate. 

 M'Intosh and Prince. — " On the Development and Life-Histories of the 



Teleostean Food and other Fishes," I'rans. Boy. Socy., Edinburgh, Vol. 



xxxv., Part III. (No. 19), Plates I. to XXVIII. 

 M'Intosh and Masterman.— " British Marine Food-fishes." London, 1897. 

 Petersen. — " On some Zoological Characters of Young (Post-larval) Flat-fishes," 



Beport of the Danish Biological Station, iv. , Appendix II., 2 plates, p. 126. 



Copenhagen, 1893. 



