PACKARD. ] TRANSFORMATION OF ARTEMIA. 499 
do we find males in the degraded generations of A. salina already bear- 
ing the characters of Artemia milhausenii, and which live in the most 
saline water. However, we can plainly notice that in the salt ditches 
and in very small salt lakes drying up in summer, that the males of Ar- 
temia appear in immense numbers at a certain time of the year, and at 
a certain concentration of the salt water, as I observed it at a compara- 
tively rapid evaporation of the water of the salt-water basins at the 
time of continued drought. Here we have to give ourselves the solu- 
tion of the question about the change of this physiological function in 
consequence of the distribution of generations of a species in another 
element, together with a certain variation of other functions, and of the 
animal organism. Referring to this I mention but one of the sides, to 
which variety b. of A. salina inclines to the genus Branchipus. 
This variety has with the species the other structures in common, with 
the exception of those less noticable aberrations depending upon the 
element, 7. €., principally from the lower concentration of the salt water, 
together with their own organization. So, for instanee, are the gill- 
sacs in the variety a little smaller, but especially narrower than in the 
species; likewise in the body more of a gray than a reddish color, and 
more transparent. This form most closely approaches the variety of 
Branchipus ferox of our salt ditches, but perhaps it is the radical form 
of B. ferox and B. spinosus. 
Consequently we have, therefore, here three closely allied forms of 
Artemia: A. salina, A. salina var. a., and A. salina var.b. The species 
A. salina must justly be regarded as a double form, consisting of A. 
salina and its first variety (var. a.), as these two forms in long past 
times must have originated by division and formation of races of their 
generations from one for both middle forms. Regarding the second 
variety (var. b.), it represents a form originated from A. salina, and be- 
came distributed in salt ditches of lesser salt capacity, and it is likely 
that also a similar offspring of the second variety exists. 
These three forms, however, have so many different characters that 
they in any case can be recognized as varieties amongst themselves. 
We find such cases also in other widely-distributed species of Crus- 
taceans,! for instance, in Cyclops bicuspidatus Claus, and especially in 
Cyclops odessanus 1. sp., where two (Cyclops bicuspidatus) or still more 
(C. odessanus) near, but still differing forms under certain external con- 
ditions, each living in either its peculiar pond in one and the same, or 
also in different water basins, and where each under certain external 
conditions or at another season of the year obtains preponderance at 
least in the number of specimens. But the forms of Artemiz have the 
preference before other Crustaceans, inasmuch as the surrounding ele- 
ment includes less complicated conditions, which by the observer can 
be kept under better control. 
Among the forms of Artemiz we may regard A. milhausenti as one of 
the most retrogressively developed ones; but as one of the most pro- 
eressively developed forms we have that which I provisionally call 
variety b. of A. salina. Parallel to this A. milhausenti lives in very 
saline water, near the self-deposition of salt, or near the same (about 
23° to 25° Beaumé), but variety b. of A. salina lives in comparatively 
less saline water (4° B.). 
Our A. salina does not fully agree with that examined by Joly,’ 
1 Consult my paper in the ‘‘Schriften” of the neorussian Society of Nat. 1875, vol. 
III, 2d part. 
“Joly, Sur ’Artemia salina, Annales des Sc. Nat. 1840. 
