Of a brilliantly phosphorescent form,[6] Professor Alexander Agassiz says, “When passing through shoals of these _medusæ_, ranging in size from a pin’s head to several inches in length, the whole water becomes so wonderfully luminous that an oar dipped in the water up to the handle can be seen plainly on dark nights by the light so produced. The seat of the phosphorescence is confined to the locomotive rows; and so exceedingly sensitive are they, that the slightest shock is sufficient to make them visible by the light emitted from the eight phosphorescent plates.” [Illustration: PLATE IV. LUMINOUS SEA-JELLY AND MOLLUSK. _Beroe forsakii._ _Cranchia scabra._] Professor Agassiz also states that the _Lucernaria_[7], a handsome green sea-jelly, emits a peculiar bluish light of an exceedingly pale steel color. While all these forms are beautiful individually, their combined forces produce an array of splendors hardly to be described. Such pyrotechnic displays of Nature are best observed during the autumn, when the jellies are wrecked and stranded; the waves hurling them in, and grinding them up upon the rocks, which appear bathed in warm, lambent lights. At Spouting Horn, on the New-England coast, this luminous water is forced through a small chimney or crevice in the rocks, with a reverberating roar; sending skyward a column of gleaming water, that breaks in mid-air and falls in golden spray. In drifting along in a boat at this time, every movement of the oar produces the most astonishing results. A slight splash is followed by a blaze of light. By having a companion keep up a continuous motion of the water, I have almost been able to read the print of a newspaper by the light of these disintegrated forms. One of the most striking displays of this phenomenon I have ever witnessed was at the little port of Ogunquit, Me. Returning, one dark night, from an off-shore fishing excursion, I saw, as we approached the harbor, an irregular row of lights, apparently lanterns in the hands of friends. We hailed, and not until we were nearly in the surf were we undeceived. The rocks were lined with kelp; and, when the waves came in, the glowing, sparkling mass of _medusæ_ caught upon the weed, remaining, as the water left it suspended, a blaze of light, until the next wave broke. My companion, an old fisherman, had also been deceived by the lights; and we drifted there for some time watching these strange spectres appear and disappear.