PACKARD.] PHYLLOPODS OF NORTH AMERICA. 333 
not quite so long as in New Haven ones, but there are not even varietal 
differences in the two examples. From these comparisons it may be 
inferred that the two species should be united. | 
On comparing a number of Salt Lake females with individuals of the 
same sex of the European Artemia salina, our species was found to be 
undoubtedly specifically distinct; the Utah specimens are sienderer, 
smaller, and the sixth endite of all the feet considerably slenderer 
and longer in proportion than in A. salina. The ovisacs were of the 
same proportion but slenderer, and the head is slighter and smaller in 
our American species. 
Habits of Artemia fertilis at Great Salt Lake, Utah.—The food of the 
Artemia appears to be the smaller fragments of brownish alge which 
abound in the water, especially Polycistis Packardti of Farlow.* The 
cells of this alga are filled with molecules of protoplasm. The contents 
of the alimentary canal of alcoholic specimens of Artemia is a darkish 
mass, which, on being examined under a 3 Tolles objective, shows the 
same granulated protoplasmic mass as that to be found in the lobules 
of the alga, leaving little doubt in my mind that the partly digested 
substance in the digestive canal of the Artemia is the alga. 
At Farmington, on the shores of the lake, where there are old brine 
pools, filled with strong brine, the shallow water was crowded with 
Artemic. The water was very warm, and the Artemic were deep red 
in color, though some red ones were collected in the lake itself. They 
were afterwards observed at Lake Point July 26, 1875. The tempera- 
ture of the water in the shade at the end of the wharf was 73° F. at the 
surface, and also at the bottom at a depth of eight feet; the temperature 
of the air was 80° F. at 11 a. m. 
Out of a large number observed, from 500 to 800 individuals, but 
very few were half grown, some being from + to 4 inch long. ew soli- 
tary males were seen, as the large majority were attached by their 
claspers to the females in the attitude shown in fig. 17. The females 
far outnumbered the males, as certainly over half of them had no males. 
attached. 
The egg-sacs and eggs were in different stages of development. I 
could see no attempts at copulation, unless in one instance, where a 
male violently jerked his body; but that was perhaps simply to obtain 
a stronger hold with his claspers around the body of the female, the 
claspers being placed just in front of the ovisac. 
The eggs are light, floating on the surface of the water. They are 
dull, dirty, yellowish white. 
The nauplius (Pl. X XU, fig. 1) is blood-red, with a single sapphire-red 
eye, and it is very active. 
Four sets of Artemic were observed: 
A. Some, both males and females, entirely green. 
B. Most of the females were red in front of the abdomen, the red 
being caused by scattered pigment cells. The males attached to them 
were greenish. 
C. Some red males attached to green females. 
D. The largest females entirely deep blood-red, with distended 
ovisacs, but contaiving no eggs. 
There must be numerous sterile or parthenogenous females. There 
is a great disproportion in the numbers of the sexes. The males are 
stronger swimmers than the females, darting at certain individuals and 
then leaving them to go after others, as if exercising some choice. 
* American Naturalist, Nov., 1879, p. 702. 
