THE FLAT-FISH FAMILY 249 



The Sole (So/ea vulgaris). 



Distinguishing Characters. — The chief peculiarities of the sole 

 and other kinds resembling it are the narrow oval shape of the 

 body, presenting everywhere a regular curved outline, and the 

 character of the head. The mouth is not at the end of the 

 snout, but behind it, and the jaws are curved, not straight. The 

 outline of the snout is semicircular, and the dorsal fin commences 

 on it in front of the eyes. The eyes are small. No bones are 

 visible on the head, the scaly skin extending over all parts of 

 it equally. On the lower side of the head there are no scales, 

 but a number of short soft processes. The marginal fins 

 extend to the base of the tail fin, but are not joined on to it. 



The common sole is distinguished from others by the follow- 

 ing points : pectoral fins on both sides of considerable size ; 

 that of the upper side with a black spot at its outer end ; nostrils 

 on the two sides similar ; fin-rays, dorsal y^^ to 90, ventral 61 to 

 74. Colour, brown or greenish-brown, with rows of darker 

 blotches along the centre of the upper side, and along the 

 bases of the fins. The usual length is 12 to 18 inches, but 

 specimens have been recorded up to 26 inches long, and 11^ 

 inches broad. 



Habitat. — From the Mediterranean to the coast of Denmark 

 and the Firth of Forth, north of which latitude it is rare. It is 

 fairly abundant round the coasts of Ireland and in the Irish Sea. 

 In the Bristol Channel and the English Channel, and also in the 

 North Sea, it is taken in large numbers by the beam trawl. 



The sole is distinctly a shoal water fish. In the Irish Survey 

 the greatest number were taken between 5 and 30 fathoms, while 

 a few were taken at greater depths up to 53 fathoms, and in less 

 up to 5. The most productive sole grounds in the North Sea 

 and English Channel are from 5 to 40 fathoms in depth. 



Food. — The stomachs and intestines of soles examined from 

 December to March at Plymouth were for the most part empty, 

 probably because the spawning season was approaching. Thirty- 

 six were found containing remains of food, and in eighteen these 

 consisted of marine worms. Small fragments of the shells of 

 bivalves were present in many, but these seemed in most cases 

 to have been attached to the tubes of tube-building worms, 



