mount           mount_nfs       mount_nwfs      mount_unionfs
mount_cd9660    mount_nfs4      mount_portalfs  mountd
mount_mfs       mount_ntfs      mount_smbfs
mount_msdosfs   mount_nullfs    mount_udf

##asi lo monto!!!!
mount -t ext2fs /dev/ad0s4 /mnt/hda4/
mira la salida : 
:D:D:D:D
[marc@freebsd ~]$ mount
/dev/ad0s3a on / (ufs, local)
devfs on /dev (devfs, local)
/dev/ad0s3e on /tmp (ufs, local, soft-updates)
/dev/ad0s3f on /usr (ufs, local, soft-updates)
/dev/ad0s3d on /var (ufs, local, soft-updates)
/dev/ad0s4 on /mnt/hda4 (ext2fs, local)

Montado!!!