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Show 498 REV. S. J. WHITMEE ON PALOLA VIRIDIS. [Julie 15, the water. They move rapidly, and with considerable elegance, in a spiral manner, like a screw. The shortest, which were about 6 inches long, had generally two coils, while the longest, which were fully 18 inches long, had as many as five or six coils. The best representation of their appearance I think of is the tendril of a climbing plant, with a coil to about each three inches of its length. In places where the Palolo were plentiful they seemed to be entangled in an inextricable mass. The worms were of two colours, green and light brown *. Taking a green one into the palrn of m y hand with a little water, I subjected it to slight pressure with my finger, when it broke into pieces of from half an inch to an inch and a half in length, and each piece wriggled about until it subdivided once or twice. From each fracture there immediately flowed out an innumerable quantity of minute green eggs, until nothing was left of the pieces into which the worm had broken except thin transparent cysts. Next, taking one of the light-brown worms into m y hand, it ruptured exactly as the green one did, and from each end of the pieces a whitish fluid freely flowed, leaving, as in the green worm, only thin transparent cysts. It was evident these were the two sexes, and that, while the females were filled with ova (a small portion of each extremity excepted), the males were as completely rilled with the seminal vesicles. The question now was, how are the ova of the female fertilized 1 1 saw no sexual contact. But the secret of the appearance of the Palolo seemed solved : by this time the sun had been half an hour above the horizon ; and the worms were rapidly breaking to pieces in the sea just as those had broken which 1 took into m y hand. Where they were thickest the sea was discoloured with the milky seminal fluid which was escaping from both ends of each piece of the brown male worms; and by taking a small quantity of sea-water into the palm of m y hand, I found it to be full of the minute green eggs which had flowed from the ruptures of the green female Palolo. Hence this breaking-up appeared to be a uatural process by which the species is propagated, the eggs being fertilized by contact with the semen while floating in the spa. I felt fully convinced this was the mode of propagation of the Palolo, and that this fully accounted for its regular appearance, but resolved to wait and make another observation before communicating my opinion to the Society. I therefore visited the same place on the 11th November, 1873, hoping to have another opportunity of seeing * In the late Dr. Seemann's ' Mission to Viti,' p. 61, it is said, " They are of various colours, green, red, brown, and sometimes white." Although I have had Palolo brought to me by the natives for several years, I have never seen more than two colours; but some of the brown ones are of a lighter shade than others. I have occasionally found specimens of another annelid, which was red, mixed with a mass of Palolo. When preserved in alcohol or Goatby's solution, the brown worms get stained witli the colour of the green ones. Hence the origin of the specific name. As will appear further on, the green colour is confined to the eggs of the gravid female. Hence, except when they are full of eggs, and the brown ones are stained by the green colouring-matter, this name is inappropriate. |