Question About Unity Memory

Hello EveryBody ,I have some question With unity memory profiler. When I profiler My Game ,I find out my asset only use for 24MB memory but one thing as called Not Saved use my 219MB who can tell me what is it?
eg:

i see details in not saved and i find out mesh use 206.5MB,the same mesh can be used many times memory and one mesh cost 3.8MB memory ,how can i reduce it?
eg:

If you are using NGUI, check this.