470 GEOLOGICAL SURVEY OF THE TERRITORIES, 
small number of years, and a comparatively short series of generations, 
in a salt lake with increased density to transform itself into a form 
identical with Artemia muehlhausenti M. Kdw., whereby this form is 
ore to remain constant, as long as the surroundings are not changed. 
. Artemia is apt, in artificia ully domesticating several generations 
in ‘eal water of gradually decreased density, to progressively develop 
towards the genus Branchipus, obtaining thereby its generic characters, 
nine apodous segments. 
4. In a state of nature salt-water ditches of different density, inhab- 
ited also by the higher specialized forms of Artemia, yield the condi- 
tions for progressive development of Artemia into Branchipus. 
5. The size of the fureal lobes in Artemia, the number of bristles and 
their distribution on the tips and sides of the lobes, are, together with 
the other generic characters, depende.t on the concentration of the 
salt water inhabited by Artemia. 
6. At a lower density of the salt water occur also in certain brine 
ditches Artemiv with pretty long furcal lobes, with a considerable num- 
ber of bristles (up to 22 distributed over each lobe), similar to Branchipus. 
7. The only characteristic features distinguishing the genus Branchi- 
pus from the genus Ariemnia are: 
Firstly, the presence of cight apodous postabdominal segments, 
whereby the last eighth segment is nearly twice qs long as the preceding, 
while in Branchipus there are nine such apodous segments, of which 
neighboring segments, by twos, show but a trifling longitudinal differ- 
ence. 
Secondly, parthenogenesis occurs in Artemia, while in Branehipus it 
is not yet known to occur. 
8. The last long eighth postabdominal segment of 4rtemic is homol- 
ogous with the last two postabdominal segments of BDranchipus. 
IT have now to append a few words on the parthenogenetic propaga- 
tion of our Artemia. 
I had already observed parthenogenesis in Artemia in 1871, while ar- 
tificially domesticating several isolated generations. It being something 
new to me at that time, 1 devoted mere attention to investigations on 
the influence of surroundings on Artemia relative to morphology. 
Of three isolated generations of 2 Artemia salina 1 obtained, while 
artificially domesticating them, by parthenogenetical propagation, in 
every density of the salt water that sustained their life, only females. 
. . . L[mentioned in the “Schriften” of the third meeting of Rus- 
sian naturalists at Kiew, . . . that the males appear in the lake in 
great numbers at a moderate density of the salt water. 
For such moderate density I took the density of the Hadschibei 
Lake in the summer of 1870, 1t having been literally filled with Artemic, 
whence they were thrown on the shores in piles by the waves, where 
they decayed. 
However, I committed a mistake, overlooking an error in the protocol 
of the third meeting at Kiew, having said in my printed report that only 
at a mean (moderate?) density of the water, similar to the density of the 
preceding year (1870), by domestication as well as during the summer 
in the lake males appear, instead of having said, only at a moderate 
density of the water, similar to that of the preceding year, by domesti- 
cation as well as during the summer in the lake the males ought to ap- 
pear. As I noticed at the time, that the males of Artemia appear in the 
lake at a certain density of the water, I assumed, after I could not ob- 
tain them either at a higher or lower density, that they still ought to 
make their appearance at the density for which I took the salt water in the 
