PACKARD. ] TRANSFORMATION OF ARTEMIA. 495 
’ the mean length of Artemia salina var. a. As a rule the specimens of 
this variety are two lines or nearly so larger than the specimens of the 
species.! 
With the mean size as a point of distinction, the fact may serve to 
show that the posterior part of the body in this variety from the begin- 
ning of the first apodous segment to the end is somewhat longer than 
in the normal species. The anterior part of the body in Artemia salina 
is in proportion to the posterior part in most cases as 5 to 6 (or 5 to7 
in higher concentration of the water), but in this variety usually as 5 
to 8, slightly fluctuating to this or that side in different salt capacity of 
the water. The postabdomen in this variety is not only longer, but 
also slenderer than in the normal species. 
The furea is longer in the variety than in the species, and the number 
of bristles on the furca is also greater in the variety. If the furca in the 
species is six times shorter than the last prolonged segment of the ab- 
domen, then it is but four times shorter than that segment in the race. 
But we also meet with specimens of the species with such a proportion 
of the furca to the last segment, as in this variety, and again we see 
tureal lobes in specimens of the variety with the same proportion to the 
last segment as in the normal] species. In Artemia salina occur from 4 
to 12 bristles on each lobe of the furca, rarely more; in the variety a. 
of Artemia salina there are from 8 to 15, but seldom more. In this 
race, a8 well as in the species, we find however also less than four 
bristles on each furcal lobe; there occur three, two, and one bristle on 
each lobe, especially in more concentrated water; but such specimens 
and generations must, by modifications of other structures, be regarded 
as transitory forms between Art. salina and A. milhausenii. 
The claspers or second antenne of the males of the variety are less 
broad than in the males of the normal species. The groups of spines or 
teeth on the anterior part of the claspers, near their base, are some- 
what better developed in the males of the variety than in the males of 
the species A. salina. The second antenne of the females of this race 
are a little smaller and narrower than in the normal species, just as the 
mnale claspers are narrower than in the species. 
The specimens of the variety a. of Artemia salina are of a far darker 
red color than the specimens of the species, although there occur also 
specimens with the same color amongst the latter. The variety a. of 
A. salina is usually of a red color, and is found here in the Kujalnitzki 
salt lake, but Art. salina is usually of a grayish or reddish-gray color, 
occurring principally in the Chadschibai salt lake, in which occur also 
specimens of red color,’ which represent, as it were, the points of aber- 
ration of the species toward its race (var. a.). 
In the variety a. of Artemia salina the gill-sacs are a little smaller; 
the posterior branchial lobes, on the other hand, a little larger than in 
the normal species. According to the other structures, it does not 
differ from the species Artemia salina; and all that was said relative to 
the influence of the surrounding element about the species refers also 
to the variety a. of A. salina. 
All the characters of this variety correspond with the circumstance 
that specimens of them, in comparison with the specimens of the spe- 
cies, prosper better at a higher concentration of salt water, but at a 
lower temperature. , 
1 The specimens of the species are about 14™™ length, the specimens of this variety 
17 or 18™™, The summer generations are in one, as well as in the other form, a little 
smaller than the fall generations. 
2The Kujalnitzki Lake has more saline water than the Chadschibai Lake. 
