Bull. U. S. H, K., 102n. 



(Dc)i'. 10.-)3.) 



AR 



Fio. 2.— Typical scale of Lake Huron whiteflsh (Cortgonus cliipenformis, Mitchill) from East 

 Tawas, Mich. Length of fish, 197 millimeters; capturei October 22, 1917. L-L, length of 

 scale; F, focus; C, circuli; .!, annulus of first winter; AK, anterolateral ridges; PR, postero- 

 lateral ridges; dorsal, ventral, anterior, and caudal border and area. X25 



r;G. 3.— Scale of Lake Huron henius (i. urUdi) taken October 22. 1919, at Uuck Isle (Lake Huron). 

 Length, 232 millimeters. Female. .\ge VI (?). Scale shows a regenerated focus 



