BRAIN PATTERN 27 



function of tactile organs there was developed a specialised areas in 

 the spinal cord to receive the sensations of touch. 



It must not be assumed that there' is no tactile sensation in the 

 pectoral fin, because the most posterior rays of the fin may be seen to 

 approach in structure the sensory filaments. But the main func- 

 tion, propulsion, of the fin has been lost or altered by the develop- 

 ment of the fingers, so that two functions can be distinguished, 

 propulsion in the anterior portion and tactile sensations in the pos- 

 terior, although according to Couch the fingers at times seem to 

 act as organs of locomotion. Other examples of the change of 

 functions in a fin will be described later, when it will be necessary 

 to discuss the habits of the rockhngs and their brain pattern. 



