Hello Michael,
Thanks for getting me up to speed - that was a little too late at night...
I can't positively identify the hulu material from the nice pics - I'm pretty sure though that it's neither recent/fossil elephant molar (I can see no hints on the pics which would suggest this) nor hippo/walrus/dugong. If forced to, I'd probably bet at elephant ivory but only close examination under magnification will help to verify this. (I think the many microcracks (age?) kinda mask the regular ivory appearance you're more used to.)
Great piece and I also like the other one as much!
Regards,
Kai