492 



BULLETIN OF THE BUREAU OF FISHERIES 



particularly in Saginaw Bay and southward, often show a sprinkling of pigment; 

 and at the north end of the lake and in the North Channel and in Georgian Bay 

 individuals very frequently show pigment on all the abdominal fins. The herring 

 taken in the North Channel at Cutler (subspecies manitoulinus) are considerably 

 darker than those collected elsewhere. In such individuals the color of the back 

 in life is blue green obscured by heavy pigmentation, which extends onto the sides 

 of the body and of the head. The cranium is deep blue black, as is the snout. The 

 abdominal fins are usually very heavily pigmented, especially on the longest rays, 

 and the dorsal and caudal are likewise very dark. Specimens are taken frequently 

 elsewhere in the North Channel which show an approach to these melanistic individ- 

 uals, and specimens with heavily pigmented paired fins are not unusual in Lake 

 Huron, particularly in the northern waters and in Georgian Bay. 



All males and probably all females show pearl organs in the breeding season, 

 which do not differ in their development from those described for the Lake Erie form. 



VARIATIONS 



Racial variations. — -There is a wide variation in all characters exhibited by 

 specimens from the same school, as may be seen in Table 71. The specimens from 

 certain localities often show distinct tendencies to vary in certain directions, 

 but, with the exception of the Cutler herring, none of these local forms have 

 varied so far that they are conspicuously different from their neighbors. Many of 

 these forms, however, would certainly show average differences in certain characters, 

 but there have been so few specimens collected from any locality (except from Sagi- 

 naw Bay) that it is not possible to give here a serious treatment of these differences. 

 The fact that most of the characters that would be involved in such a comparison are 

 proportional expressions, which vary in quality with the size of the individual, 

 further reduces the significance of a study based on a few individuals. It may be 

 worth while to point out, however, that what data I have indicate that the individ- 

 uals from the North Channel will be found to have proportionally larger heads and 

 eyes, darker color, and possibly shorter paired fins than those from Lake Huron 

 proper and Georgian Bay. 



I do not agree with the findings of Jordan and Evermann (1911), who, in describ- 

 ing harengus as occurring in Lake Huron but particularly in Saginaw and Geor- 

 gian Bays, state that it differs from cisco huronius of Lake Huron proper and of 

 Georgian Bay in having a gray color, less cylindrical body, smaller size, and especially 

 in having a much smaller adipose fin. In point of color I have observed already that 

 an occasional specimen may have a paler back, be it found in what part of the lake it 

 may; but I have not been able, in my examination of several thousand individuals, 

 to confirm the general observations of these authors as to the color differences of the 

 bay forms and those of the open lake, nor have I been able to find that there were 

 differences in the degree of lateral compression of the body. As for size, it is true 

 that the fish in Saginaw Bay and some parts of Georgian Bay are of small size as a 

 rule, but this is not always the case, for in the fall of 1917 in Saginaw Bay and in 

 the fall of 1919 at Killarney, in Georgian Bay, I found a run of fish larger than usual. 

 Furthermore, size can not be considered in general a specific character, because en- 

 vironmental conditions usually control the average or maximum size of the fish in a 



