Z ART. 11. — A. IZUKA ! OBSERVATIOXS OX THE 



The worm in question is a Lycorid Polychsete which exhibits 

 nt a certain period of the year, a most remarkable swarming 

 habit for the purpose of breeding, which so closely resembles 

 that of the so-called " Palolo " worms of the South Pacific 

 (Eunice viridis' 1 ') and of the Atlantic (Eunice fucataf), that it 

 seems not altogether inappropriate to give it the title of the 

 Japanese " Palolo." However, our Japanese " Palolo," as will 

 soon be shown, is systematically quite distinct from both the 

 South Pacific and the Atlantic form ; it is referable to the family 

 Lycorida?, not to the Eunicida?. It further shows certain differences 

 in circumstances connected with the process of swarming. 



All the three forms mentioned seem to burrow in the bottom 

 during the immature stage. With the attainment of sexual 

 maturity and under certain peculiar conditions, the part of the 

 body with sexually developed segments swarms out. In the 

 Pacific and the Atlantic " Palolo," the sexual segments are in 

 the posterior portion of the body; this portion becomes detached 

 from the anterior and is known to do the breeding-swarm. 

 Contrariwise in the Japanese " Palolo," the sexual segments are 

 confined to the anterior portion, which alone does the swarming 

 after shedding off the posterior, shrunken, non-sexual segments. 



As regards the period of the year when the swarming takes 

 place, it is known that in the " Palolo " of both the Atlantic 



* For accounts of tins worm, see: S. J. Whitmer, On the habits of Palolo viridis. Proc. 

 Zoöl. Sue. London, 1S7Ô, P. 496-502.— W. C. McIntosh, Report on Annellida. Chill. Rep. 

 X[f., 1885, pp. 231-235 (Stauracephalus) ; pp. 257-2(1] (Palolo viridis). — A. Collin, Ueber den 

 Palolowurm. Appendix to A. Kramer's Feber den Bun der Korallenriffe, etc. Kiel u. Leipzig, 

 1S97.— B. Friedlander, Ueber den sogenannten Palolowurm. Biol. Centralblatt, XVIII., 

 1898, pp. ?>37-357. — A. Agassi/,, Islands and Coral Reef of the Fiji Group, Am. Jour. Sei., 

 ser. 4, V., 1898, p. 123.— A. G. Mayer, An Atlantic Palolo, etc. Hull. Mus. Comp. Zool., 

 XXXVI., 1900, pp. 1-14. 



f For the latest account of this worm, see A. G. Mayer, The Atlantic Palolo. Science 

 Bulletin, Mus. Brooklyn Institute of Arts and Sciences, I., 1900, pp. 93—10,*. 



