Need Help With Experiment

[Terry J. Peek]

I am trying to differentiate between Serratia marcescens and a gram pos. cocci 
that I suspect is Staph epidermidis or S. aureus. I've placed the culture on 
10% NaCl agar. I'll check the results later this morning. What is the best way 
to seperate these organisms using the resources of a small college lab? Is my 
first step in the right direction? Any suggestions would be appreciated. 
Thanks.       Terry