>I have several specimens of C. hesitata, as well as h. beddomi and
>h. capricornica and wondered about the nacre of these shells...
>The pictures I've seen of C. armeniaca appear to have a 'typical'
>glossy nacre (typical of many Cypraea anyway) but the hesitata, h.
>beddomi and h. capricornica have what I would describe as a "matte"
>finish to their nacre.   Why are they different in this way, while
>all are members of Umbilia?   Or does C. armeniaca have a matte-like
>finish as well?

Cypraea inductura ("callus"), I think you will find, is smooth down
to a microscopic level. That of Umbilia (one of the few good genera
in the family) probably have what is called shagreen sculpture, which
consists of small anastomosing pustules etc; in some gastropods this
is large enough to be naked-eye-visible; in others it's microscopic.

 From memory some volutids and olivids have visible shagreen sculpture.

Strictly speaking nacre is so-called mother-of-pearl, as found in
triochids, pleurotomariids etc.
--
Andrew Grebneff
Dunedin, New Zealand
64 (3) 473-8863
<[log in to unmask]>
Fossil preparator
Seashell, Macintosh & VW/Toyota van nut
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I want your sinistral gastropods!
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Opinions in this e-mail are my own, not those of my institution
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