356 



BULLETIN OF THE BUREAU OF FISHERIES 



H/S: 



Michigan, (3.2) 3.3-3.6 (4). 13 

 Huron, (3) 3.2-3.5 (3.6). 

 Pv/P: 



Michigan, (1.5) 1.6-1.8 (2.1). 

 Huron, (1.3) 1.5-1.8 (2.1). 

 Av/V: 



Michigan, (1.1) 1.2-1.5 (1.6). 



Huron, (1) 1.2-1.4 (1.6). 

 Pectoral rays: 



Michigan, (14) 16-17 (20). 



Huron, (15) 17-18 (19). 

 Scale rows: 



Michigan, (38) 41-44 (46), (31) 33-37 (38), (22) 24-26 (27) 

 Huron, (36) 40-42 (45), (30) 32-35 (36), (22) 24-26. 16 



It appears that the Huron race has, on the average, somewhat fewer lateral-line 

 scales and scale rows, more pectoral rays, a somewhat longer head and possibly 

 snout, and paired fins. The number of specimens compared for proportions is 219 

 for Huron and 74 for Michigan, with those from Huron averaging longer. Inasmuch 

 as in most fishes the head decreases in relative size with age, the smaller size of the 

 Michigan specimens makes the difference in proportion more significant. The 

 Huron form also shows more pigment. The premaxillaries are never immaculate, 

 as in the Michigan form, but usually are as densely pigmented as the top of the 

 head, and the fins (except the ventrals) are, on the average, somewhat more pig- 

 mented. Specimens from Georgian Bay sometimes have pigmented maxillaries, 

 but the maxillaries of those from Lake Huron proper usually are immaculate. 



The color in life is as in the Michigan form except for the details of pigment 

 recorded above. 



Males of the species in Lake Huron also acquire pearls in the breeding season. 

 Males taken on October 6, 1919, in 70 fathoms off White Bluff in Georgian Bay still 

 had traces of pearls. The females taken on this date were spent. It is assumed, 

 then, that the breeding season was past and that the pearls of the males were declin- 

 ing. There were no features of the state of development observed to indicate that 

 the full nuptial adornment of the Huron males would be different from that described 

 for the males of Lake Michigan. 



VARIATIONS 



Racial variations. — Virtually all the specimens collected originated in Lake 

 Huron off Alpena and in Georgian Bay. Making allowance for the greater size of 

 the fish from Georgian Bay, where the net mesh is larger than in Lake Huron, there 

 are no discernible differences in the systematic characters of the two groups except 

 the detail of pigmentation previously referred to. 



Size variations .—In Table 19, 20 specimens are extensively compared, half of 

 them less than 200 millimeters in length and half of them more than 200 millimeters. 

 In Tables 8 to 11 certain systematic characters are given for all the specimens of the 

 collection similarly separated according to size. From these tables it may be seen 



13 Forty-seven specimens. 



11 Thirty specimens. 



15 Sixty specimens. 



