In some environments, it's hard to tell the difference between genders and species. Organisms share genetic material more easily on this planet, and that leads to some complicated taxonomy. In this case, we see a group of aquatic creatures acting as nurses for a seemingly endless field of eggs. But the network of underwater chambers in which they reside is in fact another living creature. By some categorizations, it would be considered the female of the species - it produces and to some extent nourishes the field of eggs, some of which mature to be gigantic network-chambers themselves. Whether this is an extreme example of sexual dimorphism, or the result of some sort of horizontal gene transfer is a matter of conjecture at this point.