Calicoblast layer under dactylozoid

 

Clustering proliferation of dividing symbiotic dinoflagellates in Millepora sp. medusa/egg

 I will post this image for now, and get back to it.  These symbionts infect or are drawn into the medusa/egg before liberation from the mother colony.  As far as I have seen, all medusae of a given colony are either male or female.  The larva is pre-charged with it's symbionts.   The order and nature of events during the infection process are of great interest.  

From a stack of 9 images.

Annotated image to demonstrate the dividing cells with two nuclei.  Other cells, more visible in the image above, are near enough that perhaps they are just recently divided.