PACKARD} | TRANSFORMATION OF ARTEMIA. 513 
This location corresponds to that, where in Artemia on the long segmentan 
articulation is formed, if we domesticate entire generations in gradually 
diluted salt water (especially at not too high temperature), and also to 
that location where in the Branchipide this articulation exists between 
the eighth and ninth apodous segment. It would look too forced, on 
account of a single character, to include the one assemblage in the genus 
Artemia, the other in the genus Branchipus. By this rather unnatural 
systematic treatment Branchipus stagnalis would come into the genus 
Artemia, though this species according to its characters, with the excep- 
tion of the eighth apodous segment, belongs to the genus Branchipus. 
IT note that in regard to apodous segments Branch. stagnalis has not the 
full characters of Artemia, as with it the last (eighth) apodous segment 
is not so long as compared with the preceding, as in Artemia. There 
are other structures, according to which the species of Branchipus can 
be distinguished from Artemia. Such a character is that in the males 
of Artemia the claspers toward the end, that is, in the second half (last 
joint) become broader, so that the second half is tabulate, which does 
not occur in Branchipus, since their male claspers are not tabulate; 
moreover, their first half is broader and thicker than the second.! 
The circumstance that there are often certain appendages on the clasp- 
ers or on the front of various Branchipide, and that the furca generally is 
tabulate and better developed, can be but partly regarded as a character 
of Branchipus. On the male claspers of Artemia, we see also certain 
appendages in the shape of little tuberosities for holding the female; 
we even see whole groups of denticular spines, while in certain species 
of Branchipus (Branchipus ferox Grb. and B. medius mihi) no append- 
ages at all occur on the claspers of the males. Although the branches 
of the furea in Artemia have mostly the shape of a stylet, or are conical 
in shape, there are, nevertheless, also Artemice with tabuliform branches 
of the abdominal furea, like the second variety of Artemia salina (var. 
b.), Artemia salina itself has even often a large development of the 
furca under the influence of certain external conditions. Otherwise, 
the furca of the above-mentioned Branchipus medius resembles this 
part in Artemia, only it is somewhat obliquely cut off or shoe-sole-shaped, 
curved.? Concerning the statement that the furca in Artemia was only 
terminally bristled, this is incorrect, as even in one and the same species 
the furca can be more or less developed, being bristled either terminally, 
or both terminally and laterally, according to conditions in life. But 
there is a physiological feature, which can be added to the charac- 
ters distinguishing the species of Artemia from those of Branchipus ; in 
the genus Artemia the phenomenon parthenogenesis is known to occur, 
which is unknown with Branchipus. After all this is a negative char- 
acter for Branchipus, but is important together with other structures 
in Artemia. Consequently, according to my view, the distinguishing 
characters of the genera Artemia and Branchipus are the following: 
Genus ARTEMIA. 
Hight apodous abdominal segments, of which the first two bear the exter- 
nal sexual organs, but the last about twice as long as the preceding, being 
homologous to the last two abdominal segments, the apodous eighth and 
ninth, in Branchipus. The segments of the abdomen have a considerable 
1In some species of Branchipus, like B. rubricaudatus Klunzinger, the male claspers 
are divided at the end into several branches. 
2 Consult my paper in the “‘Schriften” of the third meeting of Russ. Naturalists at 
Kiow, 1871, Zoological section, Plate II, figs. 1 to 3 and 5. 
33 H 
