# mount -o loop -t squashfs PARSIX somwhere/

mount  -o loop iso/parsix_1.5r1-i386.iso mnt/
   mount -o loop  -t squashfs  mnt/PARSIX/PARSIX squashfs/

   mount: wrong fs type, bad option, bad superblock on /dev/loop1,
       missing codepage or helper program, or other error
       In some cases useful info is found in syslog - try
       dmesg | tail  or so

 and this is the output of dmesg | tail

   SQUASHFS error: Can't find a SQUASHFS superblock on loop1