More cute worms!

In addition to Owenia there were lots of other larvae in our plankton tows. These are just two of my favorites, although everything looks cute when it's a baby! The top is some sort of polychaete, and the bottom is not technically a worm although it is worm-like.


It is a phoronid, and is most closely related to bryozoans and brachiopods. Their bodies are shaped like worms, although they have a great feathery lophophore which they use to filter water for food, and their anus loops out near their mouth. They also live in tubes, and they can brood their young in it. There are only 20 species of phoronids world wide.

Revenge of the epitokes

Another night light at FHL. This time we got the large epitokes, about as long as my forearm. You can see a shrimp trying to break the worm open to get the gametes inside later in the movie.

Night lighting

One of the way we get larvae is by lowering a light into the water at night. Many animals are photopositive, that is attracted to the light, which helps them maintain their position in the water column and find food.

By lowering the light at night, we create a sharp gradient of light and can attract a lot of animals. Most of them in this video are megalopae (baby crabs) and epitokes. The epitokes are fast, pinkish, and wiggle as they swim, while the megalopae are much bigger and chunkier.

Friday Harbor

So, I have just gone up to Friday Harbor Laboratories and have been enjoying my immersion in science after quite a long spell without. I am learning all about larval biology, so have been going on field trips to many different sites, like this mudflat pictured above, to look at egg masses and collect larvae.

One of my favorites is this Owenia sp., which is a type of worm that builds tubes out of small sandy particles. This creature has an interesting development, as the juvenile worm develops around the intestine of the larval body. When it is ready to settle, it drops out of the sac where it was developing and eats its old larval body.

Life Photo Meme: Honor an Invert

Phylum: Ctenophora

This is a nice picture of a ctenophore from Monterey Bay Aquarium. Ctenophores are often confused with jellies, as they look similar, and have only two cell layers + the mesoglea. However, ctenophores lack the special stinging cells which characterizes all members of the cnidarians (jellies, anemones, and the like). They do have special sticky cells called colloblasts, which they use for feeding. They are active predators, and can use either sticky tentacles or muscular lobes to capture their prey. the above ctenophore is a lobed variety, and catches its prey by closing those large lobes around it. You can see some of the copepods that it had for lunch in its gut.

The other way comb jellies are different from your average jelly is: the way in which this animal moves. The creature cast produced an excellent movie describing this unique (for a multi-cellular organism) mode of locomotion. If you watch, you should also be able to explain why the comb jelly in my picture has beautiful rainbow stripes...

CreatureCast - Comb Jelly Movement from Casey Dunn on Vimeo.