Sulphur-bottom \Sul`phur-bot"tom\, n. (Zool.)
A very large whalebone whale of the genus {Sibbaldius},
having a yellowish belly; especially, {Sibbaldius sulfureus}
of the North Pacific, and {Sibbaldius borealis} of the North
Atlantic; -- called also {sulphur whale}.
[1913 Webster]