The structure
of the proboscis
proboscis cavity
with fluid
proboscis pore
mouth opening
fluid in the proboscis cavity
proboscis muscle sheath—relaxed
gut
retractor muscle — relaxed
circular proboscis muscle sheath—contracted
stiletto
proboscis
gut
retractor muscle—contracted
ribbonworms
of the phylum
Nemertini, isolated
from an aquarium.
The photo on
the right shows
the protrusible
proboscis at the
anterior end of
the body.
Dr. Maik FrieDrich
anywhere near as easy as I had expected.
I didn’t want to catch the worm with my hand, as I didn’t know whether Nature had
equipped this fellow—who by all appearances was a very successful hunter—with an effective
poison mechanism. So I needed to devise another method. I eventually decided to siphon off
the knotted worm, along with the algae and sponges in its immediate vicinity, with the aid
of a wide-gauge tube. After moving the worm from the tank into a bucket, I transferred it to
a plastic bowl—but unfortunately I broke the worm in two in the process. I did note that this
creature was able to swim smoothlyin the open water, and with incredible speed! Anyone who
has had the pleasure of watching a spirited Spanish flamenco dancer will be able to imagine
the sinuous body movements of this worm, which reminded me of the undulating and twisting movements of the dancer’s dress.
A look in my books quickly revealed that it was a ribbonworm (Rhynchocoela) of the phylum
Nemertini. And I had to smile, as once again I was struck by the analogy of the Gordian Knot.
According to an ancient Greek myth, the drawbar of the war chariot of King Gordios of Phrygia,
