162 



MR. G. A. BOULEXGER ON A 



[Mar. 17, 



peduncle, tlie colonrless lower surface is squarely truncate, and the 

 truncated poi'tion, 45 niillim. in diameter, is fringed with a series 

 of I'ays, 7 in number, connected by a membi-a.ne which forms a 

 continumn with the dorsal and anal fins. Just in fi'ont of this 

 truncature, the lateral line divides into two branches terminating 

 at the base of the abnormal fin. Behind the truncated part, which 



Text-fie'. 28. 



Coloured side of iiialformed Plaice, caudal end. 



is thin and contains bony supports to the fin-rays, and separated 

 from it by a deep groove, the normal region reappears, normal 

 but for the fact that the two sides are scaled and coloured exactly 

 alike, instead of the lower side being colourless and clad with 

 smaller scales. 



Mr. Bouleuger suggests as an explanation of this wonderful 



