Hermissenda crassicornis, round 3

Species: Hermissenda crassicornis

Phylum: Mollusca

Class: Gastropoda

Order: Opisthobranchia

Sometimes you get the bear, and sometimes the bear gets you. On Friday 4/26, Chris and I went collecting out on the cable in the HMS kelp bed. We found a fresh Hermissenda egg mass on a piece of Pugettia firma, along with another nudibranch who later laid in the sea table. I split the eggs up into two mixed cultures in order to prevent overcrowding, and then added Plumularia (a thecate hydroid) to our original culture in order to induce metamorphosis. Unfortunately, the Plumularia (or something attached to it) released a mucous film that killed the entire culture, so we're now relying on the two most recent cultures to produce juveniles before the end of the quarter. When the time comes, I will experiment with several different thecate hydroids in multiple small cultures to maximize the possibility of metamorphosis. For the time being, though, here are some pictures of our new friends:

Egg mass on Pugettia firma section

                                        

Late stage cleaving embryo:

                           

Embryos in egg capsules:

                                          

Early transformation to veligers:

Early transformation to veligers (note the cilia):

Early and more developed veligers preparing to hatch:

                                

Veligers ready to hatch:

Recently hatched veliger:

- Andrew Miller