PACKARD.] TRANSFORMATION OF ARTEMIA. A91 
change of concentration in the artificial domestication yielded. The 
temperature hereby co-operates with the concentration of the water. 
Relating to this, the forms of the genus Artemia deserve special atten- 
tion. 
1.—Artemia salina Milne-Edwards. 
This species occurs here in the closed Chadschibai and Kujalnitzki 
Lake and in the salt-water ditches. It sustains a fluctuation easily 
noted in the variation of body-parts, and in its growth at a fluctuation 
of the concentration of the salt water from 5° to 12° Beaumé, in which 
limits it was found by mein the water basins. Ataconcentration of the 
salt water which is higher than 12° (and still more than 15°) Beaumé, 
our Artemia salina commences in its generations to exhibit transitory 
forms towards Artemia milhausenit Milne-Edw., the latter living by a 
far greater concentration of the salt water than Artemia salina, that is, 
at self-deposition of salt or not far from it, 7. ¢., at 24° and 25° Beaumé, 
To the description of Artemia salina given by the authors we have to 
say, that the representation of characters of this species, as altogether 
of the whole genus Artemia in the present. time, is very inexact and 
vague. Firstly, we find mentioned that Artemia possesses but six 
terminal segments, while there are eight, since we have to count also 
these two first apodous segments of the posterior part of the body, on 
which, in the species of Artemia-genera, the external genitals occur. 
Grube,! in making of Artemia a section or a sub-genus of the genus 
Branchipus, repeats the mistake of his predecessors, saying, in the dia- 
gnosis of the group Artemia “‘segmentis apodibus sex.” Only in Artemia 
milhausenti, which lives at avery high concentration of the salt water, are 
the articulations between the segments, especially between the more pos- 
terior ones, Some what less distinct; but we can nevertheless, at least in 
specimens bearing the characters of this species from our districts (also 
from the Krimea), always distinguish them, especially in fresh material 
which has not. been preserved in weak alcohol for along time. In the lat- 
ter case, even in Artemia salina, only with difficulty can we see the articu- 
lations of the abdomen. If in any region Artemia milhausenti occurs 
with connate, apodous segments, be it in some or all specimens, then it 
is very likely that we, even in such an Artemia, cannot count six apo- 
dous segments. Secondly, it has been considered hitherto as the prin- 
cipal characters of the genus Artemia, that in the species of this genus 
the abdomen ends with a short furca, whose branches are bristles only 
on the end, and such a diagnosis of the genus Artemia we discover even 
in the very latest zoological hand-book. Grube’ repeats in the diagnosis 
of his group Artemia in the genus Branchipus the characteristics of the 
genus Artemia of his predecessors, in saying: Appendicibus caudalibus 
brevibus, apice tantum .setosis aut nullis. Our Artemia and two of its 
varieties, which I shall mention later on, have the bristles not only on 
the end but also on the sides of the furcal lobes, just as in the species of 
Branchipus, which usually only have more bristles. Besides the Arte- 
mia salina from the district of Odessa I have the same distribution of 
bristles on the furca in specimens of this species brought from the neigh- 
borhood of Astrachan and the Krimea. We have here dry years with 
@ hot summer where the concentration of the salt water in the Chad- 
schibai Lake is too high for Artemia salina. Then many specimens of 
this species have, especially in summer, bristles only on the end of the 
1“‘Bemerkungen iiber die Phyllopoden” in “Archiv fiir Naturgeschichte,” 1853, p. 
139. 
2 Opus citatum, ibidem. 
