29 — Not the hydroids you are looking for #15

Thecate hydroids, Ngapipi Bridge 20/8/16

Not the hydroids you are looking for #15.

If you look closely you can see the individual polyps along each branch of the colony.

Athecate hydroids, Ngapipi Bridge, 20/9/16

The next picture shows an athecate hydroid colony. On each branch you can see each polyp as a small bud-like structure sticking up from the branch. In order to identify these animals to species it's necessary to cut bits off and look at them under a microscope.

This particular colony is growing on the dead skeleton of another athecate hydroid colony. The flesh-coloured area lower-left is a sponge. Both these pictures were taken underneath Ngapipi Bridge, along Auckland's Tamaki Drive, 20/9/16.


More info:

See Day 11 and Day 27.