Page:Natural History, Mollusca.djvu/336

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324
TUNICATA.—SALPADÆ.

light around to a far stronger degree, illuminating the ship. On taking in the towing-net, it was found half filled with Pyrosoma (Atlanticum?), which shone with a beautiful pale-greenish light; and there were also a few shell-fish in the net at the same time. After the mass had been passed through, the light was still seen astern, until it became invisible in the distance; and the whole of the ocean then became hidden in darkness as before this took place. The scene was as novel as beautiful and interesting; more so from my having ascertained, by capturing luminous animals, the cause of the phenomenon.

"The second occasion of my meeting these creatures was not exactly similar to the preceding; but though also limited, was curious, as occurring in a high latitude, during the winter season. It was on the 19th of August, the weather dark and gloomy, with light breezes from north-north-east, in latitude 40° 30' south, and longitude 138° 3' east, being then distant about 368 miles from King's Island (at the western entrance of Bass's Straits). It was about eight o'clock p.m. when the ship's wake was perceived to be luminous; and scintillations of the same light were also abundant around. As this was unusual, and had not been seen before, and it occasionally, also, appeared in larger and smaller detached masses, giving out a high degree of brilliancy,—to ascertain the cause, so unusual in high latitudes during the winter season, I threw the towing-net overboard, and in twenty minutes succeeded in capturing several Pyrosomata, giving out their usual pale-green light; and it was, no doubt, detached groups of these animals that were the occasion of the light