1900] MICROSCOPICAL JOURJNAL. 223 



Germany, where they have been successfully hatched by 

 Sibold. It would be interesting to determine whether 

 the fertilized eggs and those of parthenogenetic origin 

 are of equal vitality under unfavorable conditions. In the 

 light of known facta concerning reproduction among other 

 forms, it would be reasonable to expect that unfertilized 

 eggs would prove less able to withstand vicissitude. 



The following remarks by Gilbert regarding the brine 

 shrimp are of interest : "Packard ascribes the phenom- 

 ena^l abundance of the Artemia to the absence of enemies, 

 for the brine sustains no carnivorous species of any sort. 

 The genus is not known to live in fresh water or water of 

 feeble salinity, but commonly makes its appearance when 

 feebly saline waters are concentrated by evaporation. It 

 has been ascertained that a European species takes on the 

 characters of another genus, Branchinecta when it is bred 

 through a series of generations in brine gradually diluted 

 to freshness ; and conversely, that it may be derived from 

 Brarichifiecta by gradual increase in the salinity of the 

 medium. It is found, moreover, that its eggs remain fer- 

 tile for indefinite periods in the dry condition, so that 

 whatever may have been the history of the climate of the 

 Bonneville Basin, the present occurrence of the Artemia 

 involves no mystery. During the Bonneville epoch its an- 

 cestors may have lived in the fresh waters of the basin, 

 and during the epoch of extreme desiccation, when the 

 bed of Gfreat Salt Lake assumed the playa condition, and 

 was dry a portion of the year, the persistent fertility of 

 its eggs may have preserved the race. Or, if the playa 

 condition with its concomitant sedimentation was fatal to 

 the species, it may be that tlie alternative fresh water 

 form survived in upper lakes and streams of the basin so 

 as to re-slock the lower lake whenever it afforded favor- 

 able conditions." 



The lake flora has received even less attention than has 

 been bestowed u[)on its limited fauna. The existence of 



