Distribution of the Salmonide. 311 
Grande. Salmo stomias dwells in the Upper Missouri and in the 
Kansas River. It is the most easterly of all our black-spotted trout. 
Salmo purpuratus has hyoid teeth, and, in all its varieties, 
bears a crimson blotch on the under surface of the head, which is 
characteristic of the species. It has, also, small scales, which diminish 
progressively in henshawi, pleuriticus, and stomias. 
Clark’s Trout (Salmo purpuratus). Sitka, Alaska. About # natural length. 
The eastern limit of our species of Fario, as already stated, is 
reached by the Salmo stomias. East of the Mississippi Valley no 
Species of this genus are found native. The distribution of the 
species of Fario would seem to indicate that they originated in Asia 
or the Continent of Europe and migrated both to the eastward and 
the westward. In America the eastward distribution was checked 
by the plains of the middle region, which do not furnish conditions 
favorable to salmon-life; and the ocean barrier on the east pre- 
vented the spread of Fario into our Atlantic streams. If these 
black-spotted species were better adapted for Arctic life, their range 
might have been similar to that of the red-spotted charr. 
Before leaving the black-spotted salmonoids, it may be well to 
add something concerning the singular Huchen or Rothfisch of the 
ube. The genus Hucho has very small scales, pyloric ceca very 
numerous, gill-rakers short and few, vertebre sixty-eight, a forked 
_ caudal, a remarkably broad maxilla, with a well-developed supple 
mental bone, a pike-like skull, and peculiar dentition; the jaw 
=e armed with strong teeth ; the vomerines and palatines are strong 
and 1n a continuous series—the palatine portion very long; tongue 
With teeth ; hyoid toothless. The range of the single known specie 
appears to be very restricted. pe 
The genus Cristivomer, which appears to be only a section of Sal- 
