PACKARD.] TRANSFORMATION OF ARTEMIA. 511 
segments of Branchipus; of this no indications occur in literature. 
That Artemia salina observed by Joly has eight apodous abdominal 
segments with a very prolonged last segment can be seen from Joly’s 
illustrations, and also from this, that he counts six apodous abdominal 
segments without including the two first apodous abdominal segments 
which bear the external sexual organs. According to Rathke, who ob- 
served alcoholic specimens of Artemia milhausenti (Art. salina Rathke), 
the postabdomen is indistinetly divided into segments; he did not indi- 
cate how many segments there are. Our degraded generations of 
Artemia salina with the character of Artemia milhausenii have justasmany 
apodous abdominal segments as Artemia salina, only the articulation 
is more distinct. In the description of Artemia arietina 8. Fischer and 
Artemia képpeniana S. Fischer nothing was said about the number of 
apodous abdominal segments. Grube very incorreetly states the num- 
ber of apodous segments in Artemia as being six, incorrect, for because 
right after in another diagnosis he correctly mentions in his subgenus 
Branchipus nine apodous segments, thus showing which segments of 
the abdomen he considers as apodous. Joly gave oceasion for this 
conclusion in omitting the two first apodous segments of the abdomen, 
whichin Artemia, as wellasin Branchipus, bear the external sexual organs. 
In the other mostly examined alcoholic specimens of Artemia, the artic- 
ulation is not very plain tosee. In this regard Branchipus oudneyi Lie- 
vin (Artemia oudneyi Baird’s) deserves attention, under which name an 
Artenia from a salt lake in Africa was described by Dr. Lievin.! This 
African form has in the illustrations eight apodous abdominal segments, 
of which the first only bears the external genitals, the last being short, 
at least shorter than the preceding. Although this form, asin Artemia, 
has eight apodous abdominal segments, it can nevertheless in this pro- 
portion be included neither with the genus Artemia nor with the genus 
Branchipus. But the illustration now does not correspond at all with 
the description of the posterior part of the body of this Artemia. It 
is said in the description” that the specimens examined had laid a long 
time in alcohol, and that therefore the number of abdominal segments 
could not exactly be determined; that the abdomen of some specimens 
answered as if to one segment only, while in others four could be distin- 
guished, again, in others five segments; but from the fifth in the others 
they could not be distinctly seen. Dr. Lievin considers the presence 
of eight abdominal segments as probable. Here the author understands 
as abdomen only the whole of the apodous abdominal segments. Ac- 
cordingly, the number of apodous abdominal segments of this Artemia- 
form, and also their proportion to each other, is considered as unknown. 
It appears to me that with the absence of certain characters in Arte- 
mia for distinction from Branchipus, we must assuine eight apodous ab- 
dominal segments. Of these the first two bear the external genitals, 
but the last, terminating with a furca, is nearly twice as long as the 
preceding, and is homologous with the two last apodous abdominal 
segments in Branchipus. ‘The latter possess at the end of the abdomen, 
besides these segments, also abdominal appendages, mostly separated 
from the last segment by an articulation. In Artemia the last abdomi- 
nal segment is only somewhat shorter than the double length of the 
penultimate segment, sometimes even a little longer. Here I have to 
remark that in young, though fully developed specimens, the relative 
length of this segment is more considerable than in old ones, as the 
1Lievin, ‘‘ Branchipus oudneyi, the Tezzanworm,” in ‘ Feueste Schriften der Natur- 
forschanden Geselesch. zu Danzig.” Vol. V. 
2 Loe. cit., pp. 8 to 9. 
