506 GEOLOGICAL SURVEY OF THE TERRITORIES. 
less, ie in the disposition of the generations to distribute themselves in 
much varied elements, thatis, to distribute themselves beyond the limits _ 
of that element, at which, in the generations, the typical characters of 
the species preserve, regardless as to the causation of such distribution, 
by increased augmentation of the individuals, or of such external infiu- 
ences, like modification of the element in a given locality. Our individ- 
uals with the characters of A. milhausenti actually represent the degraded 
and modified generations of A. salina, by the itself rapidly changing ele- 
ment which also influences the Artemia living init. Similarly, like cer- 
tain annual species, which with their generations are much distributed, 
according to the seasons of the year, represent rather great differences in 
spring and summer forms. As the most extreme generations of the 
seasonably distributed species deviate from their species-type toward 
the nearest allied forms, as is seen, for instance, in Cyclops brevicaudatus 
Claus, and Daphnia magna, Leydig, var.,! so likewise deviates Artemia 
salina with its generations at the mostextreme limits of endurable concen- 
tration of the salt water toward the forms allied to them. But there is 
a great difference between these phenomena. Artemia salina changes 
during the course of several years in the direction toward A. milhausenii, 
passing through a comparatively large series of generations, and 
whereby we, in comparison, finally obtain a far greater modilication 
than any hitherto known deviation in the generations distributed sea- 
sonally. If there actually exists in nature a self-sustaining species, A. 
milhausenti, like an A. koeppeniana Fischer, besides the degraded yen- 
erations of A. salina and similar forms, then such degraded generations 
of the highest species of Artemis represent transitory forms toward the 
lower species of this genus, and indicate the element under whose influ- 
ence the latter originated. ‘This element must be a salt water of great 
concentration, together with heightened temperature. Itis possible that 
in long-continued duration of the salt-lake element peculiar to the low- 
est Artemia, the degraded generations of the higher species of this genus 
still more degenerate, rendering their characters more permanent, but 
the forms themselves more independent, even if the principal condition 
of the origin of independent forms consists in the distribution of genera-— 
tions of these forms producing species in a heterogeneous element, but 
not (or less) in the modifications of the element of a known district or of 
a certain water-basin. It seems to me that, with a very gradual increase 
of the concentration of the salt lake, the species populating it will rather 
die off in this location, than producing a new self, sustaining itself with 
the element modifying species. 
In view of such phenomena a strict scrutiny of such lowest Artemiz 
as A. milhausenit is unconditionally necessary ; all the more, since these 
species were described by the authors for the greater part from alcoholic 
specimens, and moreover at a time in which the modifying effect of the 
salt water upon the Artemiz was yet entirely unknown. 
To solve the question, whether A. milhausenii exists as a self-sus- 
taining species, I visited during the middle of July, 1876, the Krimea and 
examined specimens of Artemiz from that salt lake, which is located 
near the Tatare village Sakki on the way between Eupatoria (Koslov) 
and Simpherpolis, from which the authors (Fisher von Waldheim, H. 
Rathke, 8. Fischer), who described the Artemia milhausenti obtained 
their Artemiz. I saw that in this lake occurred already at the self-depo- 
sition of salt specimens fully answering the descriptions of Artemia 
1Consult my paper in the “Schriften” of the Neoruss. Soc. of Naturalists. 1875. 
Vol. iii., Pp. 138 to 44 and 206 to 214. 
