On the lateral line sensory canal system in Cynoglossus semifasciatus Day

In the flatfishes of the family Cynoglossidae, the lateral line sensory canals—their presence or absence on either side of the body and the number of the canals when present—are used as a taxonomic character, and the mode of branching and general configuration of the lateral line sensory canal system presents a good deal of variation from species to species (Day, 1878; Norman, 1928 and 1934; Weber and Beaufort, 1929; Munro, 1955; Punpoka, 1964). It is also found that in almost all forms of the family these canals extend onto the different parts of the surface of the head region forming a system of variable degrees of complexity. No detailed descriptions of this canal system are available for the Indian flatfishes. Ochiai (1966) has worked on this system in some detail in the case of eight species of Japanese soles. The present paper gives a description of the lateral line system in the Malabar sole, Cynoglossus semifasciatus Day with an account of some abnormalities noticed, with a special reference to certain cases of ambicolouration and albinism