nudibranch reproduction

Hey,

Y'all familiar with nudibranches? They are the colorful
sea slugs they got in them tide pools down in La Jolla?
Some of the big purple ones weigh several pounds.

Sometimes called sea cows since they 'graze' on the
grass.

They have got the largest neurons ever found so
neurobiologists use them for testing and their 'brain'
such as it is is the only one that has been fully
mapped -- all 87 neurons or whatever # it is.

Anyway, does any one know much about their mating
habits?

Also, info on mating habits of other mollusks would be
helpful as well as any advance warnings on any
contentious issues involved in this field of study. I
wonder if the conches have to come out of their shells
to mate or how that works...

Thanks,

Jeff