Sorry folks, I am sure that if I found the right faq I could locate the answer to this question, but I have done a lot of googling without success. So please forgive.
Question: Lewis Thomas famously wrote a mind-bending essay "The Medusa and the Snail", concerning a marvellous symbiotic reproductive relationship between a polyp and a nudibranch. Unfortunately he gave no references. Can anyone here please tell me which species might have been involved and add any comments on that or similar life histories? References, esp. on-line, particularly appreciated.
Much thanks if so.

Go well,

Jon