MancJiester Memoirs, Vol. hi. (191 2), No. Vt. 13' 



work has yet to be done to ascertain what conditions 

 influence the growth of the scales and the formation of 

 the annuh'. It cannot only be additional food which 

 causes increase in the number of annuli, because in the 

 same fish there is such great variation in this respect. 



Another very important point which should be 

 specially noticed in the results is that the scales to be 

 used for the comparison of different fish should all 

 be taken from very definite and restricted areas. If 

 care is not taken in this respect, variations in the scales 

 of the individual will greatly hinder true comparisons 

 being made of the scales from different fish. 



Summary. 



The special points which are brought out in this paper 

 are as follows : — 



I. A great variation in the number of annuli and 

 in the lengths of the scales taken from different parts 

 of the same fish is clearly indicated. This was found 

 on each of three fi.sh, but the results obtained seem 

 to be in no way correlated. 



II. It is to be noticed that in the three fish 

 examined the number of annuli in each peronidium 

 increases from the head to the adipose fin, and then 

 diminishes towards the tail. A similar increase and 

 decrease is found both on the dorsal and ventral 

 sides of the lateral line. 



III. In a comparison of scales taken from positions 

 at corresponding distances from the head on both 

 the dorsal and ventral sides of the lateral line, it is 

 seen that, as a general rule, the scales on the dorsal 

 side have fewer annuli in each peronidium than the 

 scales from the ventral side. 



