294 



Marine Microbiology 



50 



40 



30 



S 

 2 



5 20 



> 



z 

 o 



_l 



o 

 o 



10- 



20° 



5 



OSMOTIC PRESSURE- ATM. 



f0.08 tai8to25 ^0.40 



MOLARITY- ERVTHRITOL 



Fig. 4. Growth of Z. eistla at different temperatures on basic medium 



plus pentaerythritol in concentration from 0.18 M. to 0.40 M. See text for 



explanation of sharp cut-off. No growth at 30 C or 37 C. 



sistence media was similar to tliat found for other media (Fig. 

 6). The osmotic pressure optimum for each temperature was 

 the same as in previous experiments. Again no growth was ob- 

 served at 37 C. 



DISCUSSION 



These experiments show that the relation between salinity 

 optima and temperature does not necessarily result from gradients 

 of strictly ionic solutes, as might have been suspected from the 



