70 SEA-SHORE LIFE 
face of rocks, dead shells, ete. Often a number of these calcareous 
worm-tubes are seen clustered together, as in our illustration. 
When undisturbed the worm protrudes its beautiful feathered 
gills, which resemble a little passion- 
flower projecting from the mouth of 
the tube. These gills are variously 
colored in different individuals, some 
being purplish-brown banded with 
white and yellow, while others are 
yellowish-green, orange or lemon- 
yellow. At the least disturbance 
such as a shock, or a shadow, the 

gills are instantly withdrawn into the 
stony tube, and the opening stopped 
Fig. 42; Dead Scallop Shell covered by a horny disk called the ‘ opercu- 
with tubes of the Shell Worm. hairraee These worms are rarely more 
Long Island Sound, . 
than three inches long, and one- 
eighth of an inch wide. The body tapers gradually to the posterior 
end. In place of the gill-feet of the active worms, we find only a 
row of little bristles down each side, for these worms are unable to 
leave their tubes, and the legs which their remote ancestors pos- 
sessed have degenerated. There are no jaws, but the worm feeds 
upon minute organisms which are washed into its mouth by the 
movements of its feathery gills. 
The Sea Flower, (Spirohranchus tricornis), is a beautiful ani- 
mal, related to our shell-worm, but is larger and secretes its tube 
upon the surface of large coral heads, so that the tube becomes cov- 
ered by the coral, leaving the opening still at the surface. This 
opening is protected by a sharp spine, and is closed by the opercu- 
lum of the worm when it withdraws its gills. When expanded 
these gills resemble a beautiful pink or purple passion-flower, 
about three-quarters of an inch wide. If a shadow passes over the 
“flower,” however, the gills are instantly withdrawn into the tube. 
The worm is abundant off the Florida coast, West Indies and 
Bahamas. 
The Acorn Worm, ( Balanoglossus kowalerskii). This remark- 
able worm-shaped creature is found in shallow water, below low 
tide level, from Massachusetts Bay to the Carolinas. It lives 
