PACKARD. ] TRANSFORMATION OF ARTEMIA. ATT 
counting in all apodous segments, while in the Hungarian forms the 
length of the egg-sac equals the whole postabdomen, excluding the ab- 
dominal appendages. Besides, in Branchipus ferox of the salt-water 
ditches the egg-sac is not spindle-shaped, only elongate, often entirely 
oval, 7. e., not only shorter, but also broader, as in the form diagnosed 
by Chyzer. In our salt-water ditch forms the furcal lobes average in 
length the eighth part of the body length, inclusive of the furcal lobes; 
in Chyzer’s Hungarian form, as shown by the measurements, the fureal 
lobes average the fourth and a half part of the whole body length in- 
cluding them, that is, they are much longer in the Hungarian form. 
The most important difference consists in that while in Branchipus ferox 
of our salt ditches the furcal lobes have both edges bristled, in the form 
described by Chyzer only the inner edges of the lobes are bristled. 
Lastly, our salt-water ditch form measures, inclusive of the abdominal 
lobes, seventeen to twenty-two millimeters, the Hungarian form twenty- 
nine to thirty-four millimeters. Our salt-water form approaches in all 
other respects the diagnosis of Chyzer, and does not disagree with the 
determinations of Milne-Edwards and Grube. 
Besides the difference between the specimens of our salt-lake-water 
and the Hungarian fresh-water forms of Branchipus ferox, we find, after 
strict examination of the matter, that the bristles of the furcal lobes in 
our Salt-water-ditch forms, only in young animals shortly before becom- 
ing sexually mature, commence at the base of the lobes in one height, 
and that on getting older the number of bristles is lessened along the 
exterior edge, and that in the adult, and especially in old individuals, 
the bristles on the exterior edge of the furcal lobes will be seen to com- 
mence more than twice lower than on the inner edge of the same. At 
' a length of the furcal lobes of 2.5™™, in the adult form, the bristles be- 
gin on the inner edge at a distance of 0.24"™ from the base of each lobe, 
but on the exterior edge they begin at a distance of 0.52™™ from the base 
of each lobe. The bristles on the exterior edge of the lobes are in adults 
of this form more than twice shorter than those on the opposite inner 
edge, especially on the first half of the furcal lobes. The younger the 
individuals are the more trifling is the difference between the bristles of the 
inner and outer edge of the lobes. Yurthermore, in the salt-water ditches 
of low density such generations of Branchipus ferox live, whose individ- 
uals have an average size of about 22™, In these larger specimens 
the exterior edge of this or that abdominal appendage in the adult 
state has no bristles from base to the middle of the lobes. The bristles 
of the exterior edge are also shorter and more sparsely distributed than 
in the preceding form. Their egg-sac usually reaches down to the 
middle of the fifth apodous segment, and is a little longer than the egg- 
sac of the preceding form. The ditches with nearly fresh, scarcely 
saline-tasting, water harbor also still Jarger specimens of Branchipus 
Jerox, measuring some 25" in average length. In these large individ- 
uals in mature age the exterior edge of either furcal lobe is without 
bristles from base down to over the middle of each lobe. The remain- 
ing bristles are again still more sparsely placed, and also shorter than 
in the preceding form; the egg-sac is also a little longer. 
Specimens of Branchipus ferox, collected by me in ditches on Taman 
Island, in the neighborhood of the city of Kertsch, represent another 
link in the series of transitory forms between the extreme generations 
of the salt-lake and Hungarian fresh-water specimens. In the Taman 
specimens, which have a length of 30", the egg-sac reaches to the 
middle or to the end of the fifth apodous segment of the abdomen, the 
furcal lobes having nearly the same length as those of the Hungarian 
