PACKARD.] PHYLLOPODS OF NOETH AMERICA. 333 



not quite so long as in IsTew 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 fouud to be 

 undoubtedly specifically distinct; the Utah sijecimens are slenderer, 

 smaller, and the sixth endite of all the feet considerably slenderer 

 and longer in i^roportion than in A. salina. The ovisacs were of the 

 same proportion bat slenderer, and the head is slighter and smaller in 

 our American species. 



Habits of Artemia fertiUs at Great Salt Lal-e, Utah. — The food of the 

 Artemia ai)pears to be the smaller fragments of brownish algas which 

 abound in the water, especially Polycistis PaeJcardii 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 ^ Tolles objective, shows the 

 same granulated protoplasmic mass as that to be found iu the lobules 

 of the alga, leaving little doubt in my mind that the partly digested 

 substance iu 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 

 ArtemixB. The water was very warm, and the ArtemicE were deep red 

 iu 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 indivitluals, but 

 very few were half grown, some being from i to ^ inch long. Few 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 attemj^ts 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 XXII, fig. 1) is blood-red, with a single sapphire-red 

 eye, and it is very active. 



Four sets of Artemice 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 ingment 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 containing 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. 



