This tiny tube of sand we found on the on the beach is practically transparent. This is the former home of an Ice Cream Cone worm or Trumpet worm.
The worm cements the grains of sand with a protein that creates a tidy home for it to live in. The small end points upward, and the larger end (and most of the tube) is buried in the sand. We first found one of these in 2011 and we wrote about it in this blog post.
Pectinaria goldii are also known as trumpet worms based on their shape. I thought the structure of this tube was really interesting, so I got out my handy microscope to see it up close.
This really does seem to be a small miracle of tiny engineering. Below is what it looks like at 100x magnification. The walls of this are actually very solid, and each grain is perfectly fit to the adjacent ones. The sand, like the sand on the beach, is made up of bits of rock and shells.
I had to do a little research to find out what the worm looked like when it was alive, and put a sketch together to show the golden bristles at the edges and the tentacles for eating. Most of the worm lives below the sand.