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 Fischeret Zeitung, January 13th, 1903. Mr. Crichton Browne, 
from whom I have received much valuable help in dealing with the 
migratory Sa/monide, is carrying out systematic research upon this subject. 
