MAYER: STAUROCEPHALUS GREGARICUS. 3 
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worms continued to increase in numbers until the time of the rising of 
the sun, and then, as the light of the early morning fell upon them, a 
series of contractions came over the sexually ripe segments of each 
worm and the eggs or sperm were thus discharged into the water (see 
Figure 2, Plate 1). This contraction is often so sudden and so violent 
that the ripe segments are torn asunder, at short intervals, by the 
breaking of the cuticula, forming large rents through which the genital 
products escape. The 25-30 anterior segments of the worm contain no 
sexual elements, and take no part in the contraction, so that they re- 
main uninjured, and always retain their natural shape and appearance. 
After tke discharge of the sexual products the worms continue to 
swim near the surface for a considerable time, dragging their torn and 
contracted sexual segments after them. Sometimes, indeed, the con- 
traction causes the sexual segments to break away from the anterior 
portion of the worm, and they swim about, apparently suffering no in- 
convenience, although without a head. After the discharge of the eggs 
or sperm the sexual segments become very brittle, and a touch of the 
hand is often sufficient to cause them to break suddenly into small frag- 
ments. Jt seems not improbable that the torn and contracted sexual 
segments may eventually slough off from the 25-30 anterior ones, and 
that thus the life of the individual may be saved to perpetuate the 
species. This, however, is mere conjecture upon my part, for in 1898 
all of the worms which were confined in aquaria died during the course 
of the day without having thrown off their dishevelled posterior seg- 
ments ; and in 1899, when four of the worms were placed in a large 
aquarium the bottom of which was covered with sand and stones, three 
of the worms crawled under the stones, but all died within two days 
without having thrown off their contracted sexual segments. 
At 6.30 a.m. the worms began to sink down upon the sandy bottom 
of the ocean, and by nine o’clock in the morning none of them were to 
be seen. Large numbers of fish devour the worms during the time 
of swarming. 
There is little or no sexual color difference in the worms, both males 
and females being dull brick-red. The females, however, are sometimes 
of a duller and more yellowish tint than the males. The sperm is yel- 
low-buff or slightly pink in color, while the eggs are yellow or greenish 
yellow. The genital products escape in such quantity that the sea is 
rendered milky over wide areas, and long after the worms have disap- 
peared the eggs remain floating near the surface in visible windrows of 
yellowish color. 
