64 SEA-SHORE LIFE 
the original worm breaks up into a number of individuals each pro- 
vided with eyes and feelers. 
In the Palolo worms ( Hunice ) of the tropical Atlantic and Pacific 
oceans, the eggs are contained only in the posterior end of the worm; 
and this end is cast off early in the morning of the day of the last 
quarter of the moon, at the Tortugas, Florida, in July; and in the Pa- 
cific in November. This cast off end then swims upon the surface 
for about an hour, and finally contracts so as to squeeze out all of 
the eggs after which it sinks to the bottom and dies, leaving the 
eggs to develop, and the forward end of the worm to regenerate a 
new posterior part. 
The Ribbon-Worm, (Meckelia ingens, Fig. 54), is common in 
muddy or sandy beaches from South Carolina to Cape Cod where it 
lives buried beneath the ground near low water line. When fully 
stretched large individuals are about ten feet long, but when con- 
tracted even the largest are not more than five feet in length. Com- 
monly the worms are not more than three feet long and about three- 
quarters of an inch wide, being flat and ribbon-like with bluntly 
pointed ends, and of yellowish-white color. The body is slimy and 
the skin is covered with minute cilia which wave constantly. These 
however can be detected only with the microscope. 
This worm is remarkably active and is an excellent burrower, 
forcing its way through the sand with considerable rapidity. It is 
also a good swimmer, throwing its ribbon-like body into sinuous 
waving lines as it moves through the water. When disturbed it 
rapidly shoots out a long tubular proboscis which arises from a pit 
on the dorsal side of the head and is not a part of the throat. This 
proboscis is sometimes thrown out so violently that it breaks off, 
and then wriggles about very much as if it were a complete worm, 
while another proboscis is soon regenerated. The proboscis is cov- 
ered with an adhesive slime, and serves in the capture of prey ; for 
this worm feeds upon other worms which it devours entire. The 
mouth is on the lower side of the head. 
The development of the ribbon-worms or Nemerteans is interest- 
ing. The larva is helmet-shaped with a broad head region, and 
covered with cilia which enable it to swim rapidly. After a time 
parts of the outer skin sink down in four pit-like depressions into 
the body of the larva and these grow together around the intestine, 
