I have followed the below steps:

1)From sqlplus on my PC I connect to a remote database(On a Unix Box) using Host String(this creates an session on database)
2)I queried v$session like this and output given here

select sid,serial#,username,osuser,process,status from v$session;

SID SERIAL# USERNAME OSUSER PROCESS STATUS
---- --- -------------- ---------- --------- --------
1 1 oracle 18814 ACTIVE
2 1 oracle 18833 ACTIVE
3 1 oracle 18848 ACTIVE
4 1 oracle 18857 ACTIVE
5 1 oracle 18884 ACTIVE
6 1 oracle 18902 ACTIVE
7 3 SYS oracle 20055 ACTIVE
8 4 SYS Bandith 2244:1632 INACTIVE

MY QN. IS when I grep for the process id 2244:1632 at $prompt it is not displaying this process id. Can Someboxy explain why. Whereas
other processes r shown when I use ps -ef |grep

what does the ":" indicate in the process column value