GREAT LAKES COREGONIDS 



413 



especially at the beginning and close of the herring season. The herring nets are set 

 in Thunder Bay in November at depths of 6 to 30 fathoms. 



A number of specimens have been taken in the pound nets in Black Bay and 

 the vicinity of Nipigon Bay. The pounds were of such large mesh that only the largest 

 examples of the species were captured, and it is probable that the species was 

 numerous even in the environs of the nets. Oscar Anderson, of Rossport, Ontario, 

 in whose pounds most of the specimens were taken, stated that the large reighardi 

 had been present in the Moffat Strait net for most of the summer of 1922, and that 

 in early August, 1923, they were very common there. 



From the data just reviewed it appears that reighardi occurs most abundantly 

 along the shores of the bays and in the channels of the north shore. It has not been 

 found common in water deeper than 49 fathoms, and no specimens have been taken 

 from nets in water deeper than 65 fathoms. The temperature data in Table 13 

 show that the warmest waters in the lake are found within this zone of abundance. 



BREEDING HABITS 



An occasional male showing incipient pearl organs and exuding a little milt 

 on pressure was taken in the lifts made in Thunder Bay on September 15 and 17, 

 1923 (records 9, 10, and 11), but most of the fish showed green gonads. None of the 

 fish taken at Rossport, Ontario, on September 25 and 29, 1923 (records 18 and 19), 

 showed indications of sexual ripeness. The majority of females taken at Port Arthur, 

 Ontario, on November 25, 1922 (record 7), were spent, but the eggs of an occasional 

 individual were still hard in the ovary. The males also were spent, though most of 

 them yielded a little milt on pressure. The condition of the sex organs of these 

 Port Arthur fish indicates that they had spawned recently. No spawning grounds 

 of the species are known, but certainly some are to be found in Thunder Bay. 



Leucichthys reighardi reighardi of Lake Ontario 



The Lake Ontario form of reighardi resembles very closely the typical form. 

 The principal characters that can be expressed numerically are compared below: 



Gill rakers on the first branchial arch 

 Michigan, (31) 35-38 (43) 

 Ontario, (33) 35-38 (42). » 



Lateral-line scales: 



Michigan, (67) 72-81 (96) . 75 

 Ontario, (66) 73-81 (86). 



L/H: 



Michigan, (4) 4.2-4.5 (4.8). 

 Ontario, (4) 4.4-4.7 (5). 

 H/E: 



Michigan, (3.6) 3.9-4.2 (4.4). 

 Ontario, (4) 4.2-4.5 (5). 



H/S: 



Michigan, (3.5) 3.7-4 (4.4). 

 Ontario, (3.3) 3.6-3.9 (4.2). 

 H/M: 



Michigan, (2.5) 2.6-2.8 (2.9). 

 Ontario, (2.6) 2.7-2.9 (3). 

 Pv/P: 



Michigan, (1.8) 2.1-2.5 (2.8). 

 Ontario, (1.7) 2.2-2.5 (2.9). 

 Av/V: 



Michigan, (1.2) 1.4-1.7 (1.8). 

 Ontario, (1.3) 1.5-1.7 (2.1). 



From the figures it appears that Ontario specimens tend to have a proportion- 

 ally shorter head and smaller eye than the typical Lake Michigan form. These 



" These figures are based on an examination of 192 specimens of all sizes. All other figures are given for 146 specimens ranging 

 in length between 200 and 243 millimeters. Only fish taken in the southern sector of the lake are included in these tabulations. Most 

 of them are cotypes. 



78 These and succeeding figures for Lake Ontario are based on 76 collected specimens ranging in length from 203 to 295 millimeters. 



