Cartoon on connection. 

"The female anglerfish releases pheromones to attract tiny males. When a male finds her, he bites on to her and never lets go. When a male of the anglerfish species Haplophryne mollis bites into the skin of a female, he releases an enzyme that digests the skin of his mouth and her body, fusing the pair to the point where the two circulatory systems join up. The male then atrophies into nothing more than a pair of gonads. This extreme sexual dimorphism ensures that, when the female is ready to spawn, she has a mate immediately available." Theodore W. Pietsch (1975). "Precocious sexual parasitism in the deep sea ceratioid anglerfish, Cryptopsaras couesi Gill". Nature. 256 (5512): 38–40