394 



SELIG HECHT 



units, and the tail 3 units. Per unit increase in total length, the 

 head has increased 0.20 units, the body 0.50 units, and the tail 

 0.30 units. If, however, the increase of each part be divided by 

 the number of units present in that part before the growth took 

 place, we find that there has been an increase of 50 per cent 

 in each part. Hence the percentage increase in that unit of time 

 — in other words, the rate of growth — is the same for all parts 

 of the fish. 



8 10 \Z (4- 16 18 £0 22 



LEn&TH-Cn5. 



lM^:iire 10 



