THE FISH. 81 



wash the fish thoroughly, wipe it dry, and keep it in a 

 cool place. 



14. Hold the fish in the left hand, with its back up and 

 its head away from you ; insert the point of one blade 

 of the scissors at the base of the caudal fin and cut 

 the skin forward, passing to the left of the dorsal fin 

 and on to the head; remove the skin of this side, 

 carefully leaving the white muscles beneath undis- 

 turbed ; scrape part of the skin clean on the inside ; 

 note the arrangement of the scales as seen on each 

 side of the skin ; look also for traces of the lateral line 

 on the inside of the skin. Hold the skin up and look 

 through it toward the light, alternately stretching and 

 shortening it, noting especially the lateral line. Roll 

 the skin lengthwise, with the scales outermost, to see 

 how the epidermis passes from one scale to another. 



15. Observe the parallel, transverse markings on the mus- 

 cles along the body. 



16. Cut and scrape away all the muscle of this side of the 

 body down to the bones, and make out the central 

 backbone, with its bony projections above and below. 

 Bend the dorsal and anal fins from side to side, to 

 show the bones which support these fins and the rela- 

 tion of these fin-supporters to the projections of the 

 backbone. 



17. Break across the backbone under the centre of the 

 second dorsal fin, and remove one of the pieces, or 

 vertebrae, of the backbone ; clear away all muscle and 

 other tissue, and make out the following parts : — 



a. The central body, or centrum, shaped like an 

 hour-glass, and hollowed at each end. 



