I use the fs type "auto" for my cdrom drive:
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/dev/cdrom              /mnt/cdrom              auto    noauto,owner,r
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However, if I insert a cdrom with an hfs fs I get:

[root@soliton gerald]# mount /mnt/cdrom/
mount: you must specify the filesystem type

with an iso9660 fs it works. Moreover, with a floppy it also works.