263 



large for the body, and keep it from tumbling prone 

 to the bottom, as is seen in lar^e headed fishes, when 

 the pectoral fins are cut off. Next these are the ven- 

 tral fins, placed under the belly. These are always 

 seen to lie flat on the water, in whatever situation the 

 fish may be ; and they serve rather to raise or depress 

 the fish, than to assist its progressive motion. The 

 dorsal fin is situate along the ridge of the back ; and 

 serves to keep it in equilibrio. in many fishes this is 

 Banting; but in all flat fishes it is very large, as the 

 pectoral fins are proportionably small. Lastly, the 

 tail, which in some fishes is flat, and upright in others, 

 seems the grand instrument of motion ; the fins are 

 subservient toit, and give directions to its impetus, by 

 which the fish darts forward with so much velocity. 

 To explain all this, by experiment, a carp is taken, 

 avd pat into a large vessel* The fish, in a state of 

 repose, spreads all its fins, and seems to rest upon its 

 pectoral and venfral fins near the bottom : if the fish 

 folds up either of its pectoral fins, it inclines to the 

 lame side ; folding the r%ht pectoral fin, the fish in. 

 dines to the right side ; folding the left fi, it in- 

 clines to that side. When the fish desires to have a 

 retrograde motion, striking with the pectoral fins, 

 in a contrary direction produces it. Jf the fish de- 

 sires to turn, a blow from the tail sends it about ; but 

 if the tail strikes both ways, then the motion is pro. 

 gressive. 



10. There is something extremely odd in the expe- 

 riments of an ingenious man, on some of our common 

 fishes, 



" I put a banstickle, says he, in a glass jar filled 

 with water : at first it refused to eat any thing, which 

 is common with ail fishes ; but afterward it grevr 

 so tame as to take small worms out of my hand. 

 Nay, it was so bold at last, that when its belly was 

 full, it Wiiuld set up its prickles, and with all its 

 strength, make a stroke at my fingers, if put them 

 near it. 



