Oy THE STJttUCTUEE AND HABITS OJP PALOLO VIEIBIS. 393 



Eemarks on the Structure aud Habits of the Coral-reef Auuelid, 

 Palolo viridis. By the Eev. Thomas Powell, E.L.S., of 

 TJjJolu, Samoa. 



[Abstract, read March 2, 1882.] 

 The palolo * vary in length from 1 to 20 inches, and are in 

 diameter from i^ to ^ of an inch. They are of foiu' colours — 

 white, light browu or ochre, greyish indigo, and dark green. 



Those of the two former colours are males, and amongst these 

 the darker-coloiu'ed varieties are of much greater length, and are 

 also far more abundant than the white or cream-coloured ones. 

 The greyish-iudigo and dark-green varieties are females ; and of 

 these the dark-green are similarly far longer in measurement and 

 far more abundant than the others. 



"Whilst watching the living animals under the microscope, I 

 have noticed that the setse move up and down and backwards 

 and forwards with great rapidity, so as almost to recall to one's 

 mind the motion of the cilia of a rotifer. I observed that 

 this motion was attended by the rapid liberation of the eggs 

 of the female and the sperm o£ the male, through oviducts and 

 seminal ducts which extend on each side from the centre of the 

 back, between each pair of somites, and terminate on the under- 

 side between each pair of lateral appendages. I observed that 

 these ducts are smaller in the male than in the female. 



The notion that, in order to effect the liberation of the eggs 

 and of the sperm, the animals break up into small pieces is pro- 

 bably incorrect ; for I saw under the microscope, as above 

 narrated, the copious emission of the ova through the oviducts 

 without any breaking-up into parts of the parent annelid. 

 Moreover, on the very last occasion, viz. October 1880, when I 

 had an opportunit}'' of visiting the palolo-ground, I saw great 

 numbers of very long both light and dark palolo (J., e. males and 

 females) almost destitute of sperm and ova. These, when caught, 

 broke up into small cyst-like segments, from which the greater 

 part of the contents had apparently already been discharged. 

 Furthermore, when considerable quantitiea of the worms have 

 been brought to my house in a vessel, and kept a day or two, 

 they have emitted large quantities of eggs and sperm, and yet 

 have not broken up into small portions. That they should be 

 broken up into small portions on the fishing-ground is not to be 

 wondered at, seeing that the sieves are constantly plying. At 

 * See Trans, iinu. Soc. vol. xxii. p. 237. pi. xli. 



LINN. JOUBN. — ZOOLOGY, VOL. XVI. 29 



