Manchester ^Teuloirs, Vol. hi. (191 2), No. V>. 11 



Dr. Tunibull in his article in The Fiehi makes a 

 short reference to the study of scales taken from different 

 parts of the same fish. 



" The scales were found to increase in size and to 

 become more elongated from the head towards the 

 tail, and there is a corresponding increase in the 

 number of the main and duplicate ridges." 

 But beyond this there is no other reference. I have 

 already discussed the length of the scale and the number 

 of annuli. The relative sizes of the scales can be seen 

 from Diagrams 4 and 5. These were drawn from the 

 scales with a camera lucida, and the drawings were 

 reduced with a pantograph. They give some idea of 

 the sizes of the scales from various parts of the body. 

 Each scale is typical of the particular position, and 

 therefore can be used to some extent as a guide to the 

 width of the scales and their shape. From these cases 

 it would seem that the scales increase in breadth as well 

 as length from the head to the adipose fin and again 

 decrease from this point to the tail. 



General Conclusions. 



On comparing the Tables, the most remarkable fact 

 one notices is the variation both in the number of annuli 

 and in the measurements of the scales, which, in many 

 cases, must have been taken from the same square inch. 

 The measurements arc additional proof that the surface 

 dimensions of the scales cannot be used as a criterion of 

 the age of the fish. 



With regard to the annuli a question that might be 

 asked is, Can any conclusions be drawn from the number 

 of annuli in each pcronidium? At present it would be 

 rash to say that any definite number of annuli are formed 



