How to stop disks from being automagically mounted on boot?

I have a btrfs filesystem RAIDed across several disks. The machine is connected via USB to an external hard-drive bay where three disks live.

In my fstab I have a mount entry for one of the disks and the path (/dev/sdb). However, during boots Ubuntu mounts all of the disks /dev/sdc and /dev/sdd. I'd like to stop Ubuntu from mounting the other disks during boot. Is there anyway to disable auto-mounting of attached disks on boot with the exception of the ones explicitly in /etc/fstab?

Here are the contents of fstab

proc            /proc           proc    nodev,noexec,nosuid 0       0# / was on /dev/sda1 during installationUUID=eb80bbb0-7b27-4b7c-b041-639cbcae1c77 /           ext4    errors=remount-ro 0       1# swap was on /dev/sda5 during installationUUID=0e0c01be-7545-449c-86a8-60309d016534 none        swap    sw              0       0/dev/sdb /media/xbmc    btrfs   defaults  0 1

When the machine boots I find something like this:

Filesystem      Size  Used Avail Use% Mounted on/dev/sda1       294G   35G  245G  13% /udev            2.0G  4.0K  2.0G   1% /devtmpfs           791M  892K  790M   1% /runnone            5.0M     0  5.0M   0% /run/locknone            2.0G  1.6M  2.0G   1% /run/shm/dev/sdc        4.6T  1.3T  2.6T  34% /media/0868831f-d234-4172-aeab-640e580190d0/dev/sdd        4.6T  1.3T  2.6T  34% /media/0956647d-a558-2218-febt-559a647221r5/dev/sdb        4.6T  1.3T  2.6T  34% /media/xbmc