Hobby skull mugs ???

The same stall at Glenbervie that gave me mugs marked "B" and "E" (CL 1431) also offered up some skull mugs for my boy. The shape is a match for the skull-shape tiki mugs used by Orchids of Hawaii (of which I have a single example, bottom centre), except these three Hobby mugs have no footring.

I do not see this shape being available from greenware companies on google search.

three skull mugs marked "EM", "BM", and "NDE"

Unlike much Hobby stuff I see these are substantial enough to use on a daily basis.

Hobby Ceramics?
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I don't see a match here Jeremy. I do see several similarities, but the teeth and the gumline and the gap between teeth and nose is rather different.
There were other ceramic businesses where you could buy quality blanks and glaze them. Studio Ceramics do this even now. The fact that they have different initials on them tell me that they were made at one of these places. No these are not necessarily Hobbie Ceramics.

There has some been some loss of definition and minor remodelling somewhere along the line but way way back these two mugs have started from the same original.

When you compare with all the differently modelled skulls there are, and put these side by side it becomes a lot more obvious.