THEIR GENERAL CHARACTER AND STRUCTURE 21 



it is supplied, and from which some ichthyologists have inclined 

 to infer the presence of a separate sense peculiar to fishes. 

 The lateral line has no known homologue among the higher 

 vertebrates. Some German ichthyologists affirm that the age 

 of a large scaled fish, such as the carp, may be reckoned by 

 examining the perforated scales of the lateral line. In its 

 second year, they say, the fish develops a ring round the 

 perforation, and another during each succeeding year.* 



* Deutsche Fischerei Zcitung, January i3th, 1903. Mr. Crichton Browne, 

 from whom I have received much valuable help in dealing with the 

 migratory Salmonidce, is carrying out systematic research upon this subject. 



