410 



BULLETIN OF THE BUREAU OF FISHERIES 



Dorsal rays : 



Michigan, (8) 9-10 (ll). 68 

 Nipigon, (9) 10-11. 69 

 Superior, 10-11 (12) ™ 



A.nal rays: 



Michigan, (9) 10-11 (12) . 71 

 Nipigon, (10) 11-12. 72 

 Superior, (10) 11-12 (13) » 



The mandible usually is included within the upper jaw, but it is not infrequently 

 equal to it or longer. The premaxillaries are not usually vertical but make an angle 

 of 55° to 65° with the horizontal axis of the head. The mandible seldom is pigmented, 

 and the pigmentation of the prenarial area is much reduced, though the area is con- 

 spicuously darker still. The body is rather compressed, so that the body form is not sub- 

 terete. The average size attained seems to be about the same for the Superior race 

 as for the others, except that in virgin waters there are more fish larger than 250 

 millimeters. Only a single specimen longer than 290 millimeters has been seen, 

 however. 



Thus, it appears that in the matter of number of gill rakers, size of eye, and length of 

 the ventral fins, the Superior form is very like the typical one. Inrespect to the number 

 of dorsal and anal rays, the length of the mandible, position of the premaxillaries, 

 and body width it is like the dymondi form. In the matter of number of lateral-line 

 scales, length of head, maxillary, snout, and pectorals, and pigmentation of the head 

 parts it seems to be more or less intermediate between the two. As the characters 

 in which Superior specimens are predominantly like dymondi are more numerous and 

 influence most their general appearance, I have called this form dymondi also. 



The color of living specimens is much like that described for the Ontario race, 

 except that the green of the back is paler, seldom being conspicuous beneath the over- 

 lying pigmentation. Specimens in spirits are pigmented on the ventral and anal 

 more often than those of the typical form. 



No specimens in full nuptial adornment have been collected. None of the males 

 taken out of Port Arthur on November 25, 1922, showed pearl organs, but these fish 

 were transported on ice, and friction had removed the epidermal structures. An occa- 

 sional male taken in Thunder Bay in September, 1923, showed incipient pearl organs, 

 and it is certain that in the breeding season, at least, the males are pearled. 



VARIATIONS 



Racial variations. — Virtually all my specimens are from Thunder Bay or the 

 vicinity, so that nothing can be said about variations with locality. 



Size variations. — Most of the specimens in the collection were taken in 2J^- 

 inch gill nets, so that they are too equal in size to furnish data on changes with growth. 



COMPARISONS 74 



Beighardi resembles zenithicus most closely. The differences between these two 

 species are discussed on page 380. 



There is a close superficial resemblance to artedi, but there are sharp differences 

 between the two species. Reighardi is not known to have more that 42 gill rakers on 



One hundred and seventy-nine specimens. 



Eighteen specimens. 

 '» Thirty-five specimens. 

 " Forty-four specimens. 

 " Eighteen specimens. 

 " Fifty specimens. 



M Figures of proportions for reighardi and nigripinnis are based on specimens 200 millimeters or more in length; those for artedi 

 on specimens 225 millimeters or more. Proportions for kiyi and lioyi and all counts are based on specimens of all sizes. 



