MR. HANCOCK'S REPORT. 137 



tigate two points to which, as yet, but little 

 attention has been given, viz.: 1. The 

 motion of the pectoral fin in the fish, whether 

 voluntary or involuntary 1 2. The process 

 of nutrition in the young fish, how carried 

 on t 



In regard to the first point, viz,, the 

 motion of the pectoral fin, it has not, I 

 believe, yet been inquired into, whether this 

 motion, which is incessantly carried on day 

 and night during the life of the fish, be 

 voluntary or not. It has often been con- 

 jectured, and with great appearance of truth, 

 to be involuntary ; the object of this per- 

 petual motion viz., to keep a constantly 

 changing stream of water before the mouth 

 and gills of the fish, and to remove that 

 portion which has been deprived of the air 



