GREAT LAKES COREGONIDS 



443 



The color of no live fish has been recorded, but probably it does not differ from 

 that of Michigan specimens. Alcoholics do not differ materially in details of pig- 

 mentation, except that the anal and the ventrals more often show pigment. 



At least the males develop pearl organs in the breeding season. Specimens 

 obtained in November and December, 1922, had traces of nuptial excrescences, but 

 most of them had been lost by friction before the specimens were received. The 

 development of the pearls probably is like that of other members of the genus. 



VARIATIONS 



Virtually all the specimens collected have been taken off Marquette, Mich., 

 and nearly all are equal in size, so that there are no data on age or racial variations. 



The smallest collected individual, 132 millimeters long, was found sexually 

 mature. 



comparisons 8 



The kiyi closely resembles Tioyi and at all times may be confused with it. All 

 other species in Lake Superior attain greater size than Tciyi, and therefore it can be 

 confounded only with juveniles of these species. 



Kiyi has fewer gill rakers on the first branchial arch, more scales in the lateral 

 line, longer paired fins, and the base of the anal fin is relatively longer than in hoyi. 

 The body shape, as seen from the side, is less elliptical in Tciyi on account of the more 

 sudden rise of the predorsal contour. The characters that can be expressed numeri- 

 cally are compared below: 



Gill rakers on the first branchial arch: 



kiyi, (36) 37-41 (45), with 24 per cent more than 40. 



hoyi, (37) 41-44 (49), with 83 per cent more than 40. 

 Lateral-line scales: 



kiyi, (72) 76-84 (87), with 88 per cent more than 75. 



hoyi, (65) 69-78 (84), with 29 per cent more than 75. 

 Pv/P: 



kiyi, (1.1) 1.3-1.5 (1.7), with 10 per cent more than 1.5. 

 hoyi, (1.4) 1.5-1.8 (2), with 76 per cent more than 1.5. 

 Av/V: 



kiyi, (0.9) 1-1.2 (1.4), with 7 per cent more than 1.2. 

 hoyi, (0.9) 1.1-1.3 (1.6), with 36 per cent more than 1.2. 

 L/AB: 



kiyi, (7) 8-9 (10), with 8 per cent more than 9. 

 hoyi, (7.5) 9-10 (11.5), with 58 per cent more than 9. 



The dorsal contour of the head in Tciyi is more or less convex and the premaxil- 

 laries more vertical than in hoyi, in which there is almost a straight line from the tip 

 of the premaxillaries to the occiput. The effect of these lines on the outline of the 

 head, as seen from the side, makes the head of Tciyi more elongated and obtuse triangu- 

 lar, while that of hoyi is rather broad and acute triangular with the mouth at a higher 

 level. The anal fin is more often pigmented in Tciyi. The body of Tciyi is somewhat 

 darker, as a rule. 



For differences between Tciyi and zenithicus, see page 381, between Tciyi and 

 reighardi, page 411, and between Tciyi and nigripinnis, seepage 427. 



8 Figures are given in this section for all collected specimens of each species except for proportions of artedi, which are given 

 or those specimens less than 225 millimeters in length. 



