502 GEOLOGICAL SURVEY OF THE TERRITORIES. 
infirmity of its characters, in which, however, it differs from the nearest 
forms, as one species differs from another species, does not represent an 
independent or original species. At constant high or little changed 
concentration of the salt water, this form is able to produce entire series 
of generations with the characters of A. milhausenii, like an original 
species. Hven if the generations of our form with the characters of A. 
milhausenti are qualified at a certain behavior of the surrounding element 
to preserve their distinctive specific characters, then these generations 
only represent a degraded and modified torm of A, salina, or, indeed, two 
closely allied forms of A. salina, of which one represents the changed 
generations of A. eee the other the changed generation, of the first 
variety (varietas a.) of this species. 
In a short treatise in Zeitschrift f. w. Zoologie, Vol. X XV, first sup- 
plementary part, [ have spoken of the changes of the generations of A. 
salina produced by heightening the salt-capacity of the water in nature 
and by artificial domestication, whereby they received the species char- 
acters of A. milhausenti. Without repeating the same, I will only point 
cut that, together with the modifications of the postabdomen of A. 
salina, the other parts also gradually changed in the direction toward 
Artemia milhausenit, t. e., the postabdomen became more slender and 
longer, the female claspers narrower; the leg-parts also changed them- | 
selves, whereby the number of bristles and fimbriate spines of the leg- 
lobes lessened, and the gill-sacs (Claus) changed from elongate to oval, 
thus comparatively increasing their size. We obtained finally all the 
peculiar characters of A. mifiausenii, as they were described by the 
authors. 
The specimens with the characters of A. milhausemi in the Kujal- 
nitzki salt lake justly represent a degraded and changed form of A. 
salina and its first large variety (a.), for that we aiso distinguish two 
different forms of individuals with the characters of A. milhausenit. 
Some correspond with the specimens of the species, others with the 
mentioned variety of A. salina. Even if the characters of the species 
and this variety of A. salina, through degradation of their individuals, 
become somewhat obliterated, it is nevertheless still possible to distin- 
guish individuals originating "from this or from that form. Those cor- 
responding with A. salina have about 10™ length, those of the men- 
tioned variety are about 12™™ in length. In the former the post- 
abdomen is a little shorter, and the posterior or apodous segments is 
shorter than the double length of the anterior part of the body, and is 
in proportion to it on the average as 8 to 5, but in the latter the posterior 
part of the body is equal to twice the length of the anterior part, or a lit- 
tle shorter, in the proportion in the latter case of 9 to 5. In both species 
this relation moreover depends upon the age of the already sexually ma- 
ture individuals, since in alee older ones the posterior partof the body 
is longer. Moreover, the former have a less dark red color, and their 
rounded abdominal end is somewhat broadened and as if flattened in 
the direction from above downward, but the latter have a more dark red 
color and the abdominal endis less broadened, only rounded. In this way 
the specimens of A. mithausenii have two forms, but the difference of 
their characters is scarcely sufiicient to regard one of them as a true race 
in relation to the oiher, and the less so, as the deviation of the indi- 
viduals of the one or the other category on one or the other side, accord- 
ing to age, even at the time of sexual maturity, allows some transitory 
stages to be recognized between them. It is only apparent that some 
represent a degraded form of A. salina, but that others represent a de- 
graded form of variety a. of A. salina. It is necessary to remark, that 
