security question (sshd log)

[Tarapia Tapioco <comesefosse@ntani.firenze.linux.it>]

I found the following entries in my auth.log file:

sshd[22774]: scanned from 68.147.18.131 with SSH-1.0-SSH_Version_Mapper.  Don't panic.
sshd[22773]: Did not receive identification string from 68.147.18.131

What do they mean, and should I panic or not?