CANADIAN FISHERIES EXPEDITION, 1914-15 



451 



deeper water and have lived long enough to experience the totality of conditions 

 characteristic of the several regions, and consequently exhibit greater diflFerences. 



The next point is: do the cold-water individuals ever attain as low a tail per- 

 centage as those of warm water? Large individuals from the Bay of Islands show 

 the following: — 



Bay of Islands. (No. 33 station 57). 



Length (mm.). 



30 

 31 

 39 

 40 

 42 



Tail percentage. 



20 



18 



18, 20 



18, 18, 19, 19, 19 



19 



Length (mm. 



44 

 46 

 49 

 52 



Tail percentage 



17, 17 

 17 

 17 

 19 



Above 40mm. in length the Bay of Islands specimens reach a tail percentage 

 (17) equal to that of specimens between 20 and .30mm. in length from the Bay of 

 Fundy. They would appear never to reach as low a tail percentage as do those of the 

 lower gulf. 



The tail percentage is seen to be a function of the degree of maturity, although 

 the cold water seems to delay the decrease in tail percentage more than maturity. 



The general result is definite. The Bay of Islands provides conditions suitable 

 for the Arctic type, the lower part of the St. Lawrence gulf furnisher a type 

 approaching that found in the Baltic sea, and the remainder of the region shows the 

 intermediate type or the typical S. elegans. 



I 



Distribution. 

 "Acadia." 



6551—3.3 



