PALOLO (pa.-15'16) WORM (Samoan name, Fijian mbalolo or bo/o/u). one of the annelid worms (Eunice viridis) allied to Nereis, which on a certain night in November appears in im mense numbers at the surface of the shores of the Samoan and Fiji islands. It is than collected as food by the natives and considered a great delicacy. In this worm the sexual or hinder part of (epitoke), when the eggs or sperm are ripe, separates from the rest of the body and swims to the surface, where the reproductive elements are discharged, after wide]] the worm collapses and dies. The swarming, of this singu lar worm has been observed by A. Agassiz, at Bololo Point, Fiji Islands. On his arrival, before daylight, his guide fished up a few of the worms, and soon the water was full of them, both males and females, and men and women were catching them in all kinds of utensils. Their activity wonderful, and the hursting of the animal when reproduction was over was most peculiar.
The Atlantic palolo worm (Eunice lueuta) is abundant at the dry Tortugas, Fla., near Porto Rico, and probably it will be found to be widely distributed. The animal commonly lies coiled in itself within its burrow, and very often another worm (Polynoi' gr•anulata) is found sharing the same burrow. The worm does not live in new and compact coral rock, or in coquina of recent formation, hut abounds in that which is disinteL?rating and has become infested with Pholas shells. other worms. crustaceans. etc. The burrow of the palolo always opens outward at the surface of the rock, although as far as is knoNtn the worm never leaves its burrow per manently until the time of the breeding-swarm. The Atlantic palolo swarms within three days of the time of the moon's last quarter. between June 29th and July 2Sth. When the swarm occurs the hinder end of the worm crawls out backward from the burrow, and attempts to swim away from the anterior. non-sexual part,
which remains within the burrow. A constric tion appears, allowing the sexual portion to break away from the anterior part of the worm; and immediately the posterior end darts upward to the surface. upon reaching which it continues to swim hind end foremost very near to the surface of the ocean. The worms move in all directions and begin to discharge sperm or eggs through their genital outlets (nephropores), but the least stimulus, such as being lifted from the water, or the current from the stroke of an oar, will cause them to contract violently, often breaking themselves into fragments and casting the sexual products out through rents in the skin. This normally occurs as soon as the first rays of the sun fall upon the water, and in a few minutes after sunrise all the worms will have completely freed themselves of genital products. so that the ocean becomes milky with the vast quantity of sperm and eggs. Two or three hours after sun rise no worms remain to be seen. In a dense swarm there may be on an average about one worm per square foot over wide areas of the sea, commonest where the water is about six fathoms in depth. Great numbers of the worms are devoured by fishes as they sink, although they are not attacked to any great extent while on the surface. When set free the sexual ends swim vertically upward with such rapidity that they run little risk of capture. and this habit must be a great advantage to the worm. If the swim ming worm he broken into fragments each piece continues to swim backward in a normal man ner, showing that the reaction is not controlled by any one ganglion. or localized group of gan glia. but that the whole sexual end of the worm is affected by the stimulus which causes the breeding-swarm.