46. SALMONID.E THYMALLUS. 303 



line nearly straight. A small bare space behind isthmus. Dorsal fin 

 long and high, its length rather greater than the depth of body, its 

 height varying, greatest in the males; adipose fin rather small; anal 

 fin small. Gill-rakers slender, short, about 11 below the angle. Color- 

 ation brilliant, (in var. tricolor) purplish gray; young silvery; sides of 

 head with bright bluish and bronze reflections; sides of body with 

 small, black, irregular spots, most numerous posteriorly in young speci- 

 mens; ventral fins ornate, dusky, with diagonal rose-colored lines; dor- 

 sal with a black line along its base, then a rose-colored one, then a 

 blackish one, then rose-colored, blackish, and rose-colored, the last 

 stripe continued as a row of spots ; above these is a row of dusky-green 

 spots, then a row of minute rose-colored spots, then a broad dusky area, 

 the middle part of the fin tipped with rose; anal and adipose fins dusky; 

 central rays of caudal pink, outer rays dusky. Head 4f ; depth 4. 

 D. 20; A. 11; scales 8-90-9. L. 18 inches. Northern Michigan to 

 Montana, northward to Alaska and the Arctic Ocean; abounding in 

 clear, cold streams in suitable locations. Professor Milner (Kept. U. S. 

 Fish Com. 1872-'73, 740, et seq.) recognizes three distinct species, which 



seem to us rather as varieties of one species. These are 







Var. sigaaifea* Rich. 



From British America and Alaska. Has the scales smaller, (Lat. 1. 

 98), the maxillary shorter, and the head rather less than one-fifth the 

 length ; the dorsal rays are perhaps more numerous, and the fin in the 

 males much higher. 



(Coregonus signifer Rich. Franklin's Journ. 1823, 711: Salrno (Tliymalltis~) sirjnifer 

 Rich. Fauna Bor.-Amer. iii, 190; Giinther, vi, 202; Milner, Rept. U. S. Fish Coin. 

 1872^-73, 738.) 



Var. tricolor Cope. Michigan Grayling. 



From various streams in the northern part of the southern peninsula 

 of Michigan. Has a longer head than the preceding, forming a little 

 more than one-fifth the length, and the scales larger, 90-92 in the lat- 

 eral line. 



(Tlnjmallus tricolor Cope, Proc. Acad. Nat. Sci. Phila. 1865,80: Tliymallm tricolor 

 Giiuther, vi, 201 : Tlujmallus tricolor Milner, Rept. U. S. Fish. Com. 1872-73, 739, and 

 of late writers on angling generally.) 



Var. nioaitaiaias Milner. Montana Grayling. 



From the headwaters of the Missouri. Similar to tricolor, but has the 

 body deeper, the depth being about 4 in the length. 



(Thymallus montanus Milner, Rept. U. S. Fish Com. 1872-73, 741, 1874.) 



