INLAND FISHERIES. 



51 



stance, iu tlie 200 measurements taken on. Dec. 4, 1899, tlie extreme 

 sizes were 36mm. and 56mm. This nniformit}^ of size among- 

 the scallops may be accounted for by the fact that the breeding-- 

 season is short, and that the conditions of obtaining food are less 

 variable than for many species. 



The following- is a list of the average length of the specimens 

 on the various dates, with references to the ]ilates illustrating the 

 size and appearance of the scallop. The figures are from life-size 

 photographs in everj'- instance : 



1899 Set, Wklfford. 



. 42 mm 

 .44.5 " 



.56.8 " 

 .53.3 " 

 .60+ " 

 .60+ " 

 .62.75 " 

 .71.6 " 

 .79 

 . 81 

 .86 

 .85 



...Plate III. 



. . " lY. 



... " V. 



... " YI. 



... " YII. 



... " YIII. 



... " IX. 



... " X. 



... " XL 



... " XII. 



... " XIII. 



... " XIY. 



. . . . " XY. 



The interesting features of this record of growth can be pointed 

 out more readily by reference to the curve plotted iu the accom- 

 panying diagram. In the curve the heavj^ dots indicate the date 

 of measurement and the average size taken from the preceding' 

 table, i. e., the vertical distance of any dot represents the size of the 

 scallops in millimeters as indicated by the scale on the side, while 

 the horizontal distance of this dot from the left side represents 

 the age of the scallop as indicated by the scale on the bottom 

 line. By connecting the dots with a line we have a curve which 

 represents graphically the rate of growth. 



