186 SUMMARY OF CURRENT RESEARCHES RELATING TO 



tube communicate at the free end. The upper canal seems to correspond 

 to the mesodermic funnel, and the nephridium belongs to the type of 

 metanephridia seen in Polychasts. The nephridia of the adult are 

 developed from those of the larva. 



Stolons of Syllids.* — Aug. Michel describes several different types 

 of stolons : (1) acephalous, in Syllis cirropunctata sp. n. ; (2) " tetra- 

 glene," where the head is represented only by two biocular tubercles, in 

 Trypano syllis zebra; (3) " dicere," where the head bears biocular tuber- 

 cles and a pair of lateral antennas, in S. vittata ,• (4) " tetracere," where 

 the head is almost complete, with eyes, lateral antennas, and palps, in 

 S. arnica. 



Syllis vivipara.t — Aug. Michel discusses this interesting species. It 

 is viviparous, and neither male nor spermatozoon is known. It is by no 

 means common, but fourteen specimens (all females) were collected near 

 shore between the Naples Zoological Station and the port of Mergellina. 

 Almost all had the second part of the body more or less distended with 

 larvse, with 10-20 setigerous rings when they pass out. Neither 

 Goodrich or Michel found any trace of hermaphroditism. 



Atlantic Palolo.f — A. G. Mayer describes the breeding-swarm of 

 the Atlantic palolo, Eunice fucata. In habits it is quite similar to the 

 palolo of the Pacific, E. viridis, but while the Pacific form swarms on or 

 near the day of the last quarter of the moon in October and November, 

 the Atlantic form swarms within three days of the last quarter of the 

 moon, between June 29 and July 28. The annual swarming has been 

 observed only at Tortugas, Florida. 



The Atlantic palolo lives within crevices of dead coral, or limestone 

 beach-rock. The worm is usually coiled backward on itself or twisted 

 within the cavity. The sexual products are confined to the 150 posterior 

 segments, which are swollen by the contained eggs or sperms. Before 

 sunrise on the day of the breeding-swarm, the worm crawls out back- 

 wards from its burrow till all the sexual segments and part of the middle 

 of the body protrude. A vigorous corkscrew-like movement begins in 

 the sexual segments, which soon break off from the middle of the body 

 and rise vertically to the surface. When the first rays of light fall on 

 the sea, the worm begins to contract violently, the sexual products are 

 cast out through rents and tears in the dermo-muscular wall, and the 

 shrivelled cuticula sinks to the bottom. 



Experiments were made with a view to determining the nature of the 

 stimulus to which the Atlantic palolo responds when it swarms. It was 

 found that a mechanical shock would often cause the worm to cast off its 

 genital products, but even if this took place within 24 hours of the 

 normal swarming period, the eggs did not develop. In partially stagnant 

 water the worms may live, but they will not swarm. Worms were kept 

 in floating tanks in which circulation was secured by numerous holes. 

 A proportion of these worms swarmed normally within three days of the 

 usual time. But none swarmed when moonlight was excluded. 



* Comptes Rendus, cxlviii. (1909) pp. 318-20. 



t Op. cit., cxlvii. (1908) pp. 1423-5. 



j Publication, Carnegie Inst. Washington, No. 102 (1908) pp. 105-12 (1 pi.). 



