Edward Alfred Minchin

“ The vast majority of jelly-fish float in the sea, with the exumbrella upwards, the subumbrella downwards. A few species, however, attach themselves temporarily or permanently to some firm object by the exumbral surface of the body, and then the subumbral surface is directed upwards. From the centre of the subumbral surface hangs down the manubrium, like the handle of an umbrella or the clapper of a bell, bearing the mouth at its extremity. In addition to the tentacles, the margin of the umbrella bears sense-organs, which may be of several kinds and may attain a high degree of complexity. ”

“ The sense-organs of medusae are of two classes: (1) pigment spots, sensitive to light, termed ocelli, which may become elaborated into eye-like structures with lens, retina and vitreous body; (2) organs of the sense of balance or orientation, commonly termed otocysts or statocysts. ”

“ A medusa with a remarkable habit of life is Mnestra parasites, which is parasitic on the pelagic mollusc Phyllirrhoe, attaching itself to the host by its subumbral surface; its tentacles, no longer required for obtaining food, have become rudimentary. ”