FLAT-FISHES 93 



the hake and the scabbard fishes in association with the great 

 depths of the sea they inhabit ; in the hatter fish we shall note, 

 in addition to the large size of the acoustic tubercles, that the 

 granular portion extends inwards in the form of a pyramid (in 

 section) and the apices of this extension consist of accumulations 

 of large cells. 



There is reason to connect this development with direction 

 finding in the darkness of the depths where sight can be of little 

 avail ; we suggest that, as the halibut descends to two hundred 

 fathoms, this modification of the acustico-lateral area may also be 

 associated with its hunting in conditions where light does not 

 penetrate. 



