Now I understand. They are as the capsules of sharks.
Helmut

Helmut "Helix" Nisters
private:
Franz-Fischer-Str. 46
A-6020 Innsbruck / Austria / Europe
phone: 0043 / 512 / 57 32 14
e-mail: [log in to unmask]
website: www.netwing.at/nisters
office:
Natural History Department of the
Tiroler Landesmuseum Ferdinandeum Innsbruck
Feldstrasse 11a
A-6020 Innsbruck / Austria / Europe
phone: 0043 / 512 / 58 72 86 - 37
e-mail: [log in to unmask]
website: www.tiroler-landesmuseum.at


----------
Helmut,

I'd be happy to tell you.  The egg case of a skate is a dark, leathery,
rectangular capsule anywhere from 25mm to 150mm long.  It has streamers on
eacg corner which are actually hollow and allow the embryo to pump fresh sea
water through the case in order to breath.  They are often washed ashore and
are found in the drift line with seaweed and shells.  They are called
mermaid's purses because of their shape and because they are hollow.  I will
send you an image off list.

Tom Eichhorst in New Mexico, USA