PACKARD. ] TRANSFORMATION OF ARTEMIA. ADT 
toward the tip, with sides and ends bristled, whose number fluctuates 
on each lobe between 12 and 22. The furcal lobes are in length only 
two and a half times shorter than the last abdominal segment. 
This last (eighth apodous) prolonged segment of the abdomen differs 
here in the important peculiarity that it possesses, a little above its 
middle, often a more or less distinct transverse ring, like an articula- 
tion, as existing between the eighth and ninth apodous segments of the 
abdomen in the species of Branchipus, in which the fureal lobes are in 
the majority strongly developed, as it were, on account of the ninth apo- 
dous segment, which is rather short with them. This transverse ring 
is just below the last sensitive bristles, occurring in A. salina a little 
above the middle of the eighth apodous segment of the abdomen,! as 
also at the end of each of the anterior apodous segments just before the 
segmentations. If this transverse ring on the eighth prolonged apo- 
dous segment was more conspicuous in variety b. of A. salina, and if it 
was of constant occurrence, then we would have a form with nine 
apodous abdominal segments, which is one of the principal characters 
of the genus Branchipus. But since there is no actual segmentation 
on the eighth apodous abdominal segment of variety b. of A. salina, this 
race forms, remaining with the genus Artemia, a transitory link be- 
tween this genus and the genus Branchipus. With the latter genus 
the examined race possesses by far more harmony than the other hith- 
erto known forms of Artemis. The prolonged, laterally and terminally, 
bristled furcal lobes, the transverse ring between these lobes and the 
abdominal end, the shortness of the postabdomen, the lesser length in 
proportion to these parts in other Artemia forms, the greater thickness 
of the segments of the postabdomen, the more or less distinct traces of 
segmentation on the last (eighth) apodous, homologous with the two 
last (eighth and ninth apodous) segments of Branchipus, likewise also 
yet other less conspicuous characters: of Artemia salina varietas b., 
demonstrate this. 
Amongst the characters in which the examined Artemia-form incline 
to the genus Branchipus I will note two more. One of them consists in 
the presence of groups of spines on the ventral and lateral surface of the 
postabdomen, on the end of the third, fourth, fifth, sixth, and seventh 
apodous segments, anteriorly of each segmentation, and a little before 
the middle of the eighth apodous segment before the more or less notice- 
able transverse ring on this segment. On some segments occur two 
aggregations, one on each side, but on others occur four aggregations 
arranged circularly around the segment. From the middle of each ag- 
gregation arises a sensory bristle, which, together with the groups of 
spines situated near their base, can easily be seen under a magnifying 
power of 350. In A. salina and its variety a. occur, instead of groups of 
spines, on the same spot groups of cuticular cells, which do not rise 
above the surface of the integument (from which they are somewhat 
differentiated), and which give rise to one bristle arising from their midst. 
These complexes of cuticular cells in A. salina and in its variety a. are 
homologous with the mentioned complexes of spines in race b. of A. salina 
and the species of Branchipus. In domesticating several successive 
generations of the species A. salina in gradually diluted salt water, I 
obtained, together with the other corresponding characters on the post- 
1On this spot of the last segment of the abdomen we obtain the segmentation in the 
species 4. salina by domesticating several of its generationsin gradaually diluted salt 
water. Compare my paper in the “Schriften” of the third meeting of Russian natu- 
ralists at Kiew, Zoological section, pp. 71 and 87; also, my paper in Z.f. w. Z., xxv, 
1871. 
02 
