4 
bulletin of the bureau of fisheries. 
We therefore provisionally adopt the name Leucichthys for the entire group, considering the sub- 
genus Leucichthys proper as composed entirely of old world species, and placing the American species 
in three subgenera, Thrissomimus, Cisco, and Allosomus . 
We further note that in Leucichthys omul 6 to 8 rows of pearly bodies are present in the breeding 
season, as in certain species of Coregouus. None of the American species of lake herring shows these 
structures, although slight warty elevations are shown in some of our specimens of L. johannce. 
This genus Leucichthys includes the species known in America as lake herring, cisco, and tullibee, 
and the corresponding forms in northern Europe and northern Asia, known as laksild, sik, vendace, 
pollan, etc. These forms are related to the whitefish, Coregouus, agreeing with the latter in the large 
silvery scales and obsolescent teeth. In Leucichthys, however, the mouth is larger, with longer jaws, 
the lower jaw being at least as long as the upper, and the premaxillaries set nearly horizontally. The 
gillrakers are long and slender, about 30 on the lower limb. The jaws are toothless in all of our species. 
There are no teeth on the palate but minute teeth are seen on the tongue when dry. 
The species are much more active than those of Coregouus and feed more generally on small fishes. 
In general, they are less valued as food than the wliitefishes, but at least one of them ranks with the 
very best of food fishes. The group separates naturally into three subdivisions which may be called 
subgenera. 
To the first of these, Thrissomimus (which is the earlier Argyrosomus of Agassiz, the name unfor- 
tunately preoccupied), belong the typical lake herring, or laksild, both of Europe and America, fishes with 
slender bodies, silvery scales, relatively firm flesh and firm skeleton, and the general form of herring, 
to which these fishes bear much external resemblance that indicates no real affinity. All the species 
of Thrissomimus have the jaws toothless, which separates them from the Asiatic genus or subgenus 
Leucichthys. None of this group or the next one is found in the basin of Lake Winnipeg, which includes 
the Lake of the Woods, the Saskatchewan, the Rainy River, and the Red River of the North. The only 
species of the genus in this vast basin is the tullibee, Leucichthys tullibee. 
To the second group, which we call Cisco, belong the ciscoes, bluefins, blackfins, bloaters, and 
longjaws, species living in 50 or more fathoms of water, with the mouth larger than in the lake 
herring, and with the skeleton relatively feeble and the flesh softer, often saturated with fat. These 
forms are all very closely related and probably sprang from a common stock which is near the species 
called L. supernas. It is not clear that they are derived from any of the existing shore species. 
To the third group, Allosomus , belong the tullibees, robust, compressed fishes with the tail very 
short, the mouth small and the color in general more dusky than silvery. The scales are firm and the 
texture of the flesh more solid than in the lake herrings. The species of this group are mostly confined 
to the region northwest of Lake Michigan, and they are found mainly in the smaller lakes to the north- 
westward of Lake Huron, their distribution being chiefly in the Winnipeg basin. The tullibees are not 
greatly valued as food fishes, the flesh being soft and watery and inferior to that of most other Salmonidae. 
The Siberian species, Leucichthys peled (Lepechin) (= Salmo cyprinoides Pallas) is doubtless a 
tullibee or typical Allosomus. 
Besides the species found in the Great Lakes region, we give here an account of all the species of 
Leucichthys known from North America. It may be noticed that the species of each group are closely 
related to one another, that the differences are more evident in the mass, as in a boat or fish market, 
than in individual preserved specimens, that measurements are liable to fluctuation, that individual 
differences are unusually great, and finally, that in those characters usually most trustworthy in fishes, 
such as the number of scales, fin-rays, gillrakers, etc., the different species are practically in agreement. 
ANALYSIS of species of leucichthys found in the great lakes region. 
a. Caudal peduncle relatively long and slender, its length along lateral line above last ray of anal more 
than .75 length of head, its length from last ray of anal to first of caudal more than its depth; 
scales silvery, more or less loosely inserted; body more or less elongate, the depth 3.25 to 5.5 in 
length; minute teeth on tongue, none on jaws or palatines. 
