PACKAED.] TRANSFORMATION OF ARTEMIA. 491 



change of conceDtration in the artificial domestication yielded. The 

 temperature hereby co-operates with the concentration of the water. 

 Eclating to this, the forms of the genus Artemia deserve special atten- 

 tion. 



1. — Artemia salina Milne-Edicards. 



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° Beaume, in which 

 limits it was found by me in the water basins. At a concentration of tlie 

 salt water which is higher than 12° (and still more than 15°) Beaume, 

 our Artemia salhia commences in its generations to exhibit transitory 

 forms towards Artemia milhausenii 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, i. e., at 24° and 25^ Beaume, 



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 Arteinia 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 apocHbus sex^ Only in Artemia 

 milhausenii., which lives at a very high concentration of the saltwater, are 

 the articulations between the segments, especially between the more j^os- 

 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 raaterial 

 which has not been preserved in weak alcohol for a long 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 milhausenii 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, ajyice 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 specimensof this species brought from the neigh- 

 borhood of Astrachan and the Krimea. We have here dry years with 

 a 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 ouly on the end of the 



1 " Bemerknngen iiber die Pliyllopoden" in ''Archiv f iir Naturgescbiclite," 1853, p. 

 139. 

 2 Opus citatum, ibidem. 



