56 IOWA STUDIES IN NATURAL HISTORY 
tube-dwelling annelid were collected. It is necessary, however, to use 
great caution in capturing this worm, as it immediately withdraws into 
the tube if a shadow falls upon it or if the water is disturbed by the 
motion of oars. It is also necessary to work quickly; for the tube is of 
considerable length, and the inhabitant withdraws to the bottom of it 
and sometimes even escapes through the posterior end of the tube. 
Localities: Port Arthur, Jamaica; English Harbor, Antigua. 
CONCLUSION 
It is the opinion of the writer that thejspecies of Bispira just 
described was introduced at English Harbor, Antigua, probably 
at the beginning of the nineteenth century, when Nelson used 
the island as a naval base. These worms are found along the 
sea-wall at only one place on the island, namely, the dockyard 
where ships anchor. These sedentary tube-dwelling annelids 
might easily have been carried long distances attached to the 
bottom of ships or to anchors. 
This annelid, being a tube-dwelling worm, has the body high- 
ly specialized anteriorly, while posteriorly some degeneration 
has taken place. The parapodia are greatly reduced along the 
entire length of the worm. Dissections show that the septa are 
incompletely developed in the thoracic region, and sometimes 
they are absent near the head. Absence of septa allows a free 
communication between successive segments and consequently a 
freer flow of ccelomic fluid. With the disappearance of the 
septa there is a diminution in the number of nephridia. The 
ecelome in the thoracic region is filled with gray glandular tissue 
which seems to be nephridia. A large portion extends forward 
into the head, where the two nephridia unite into a common 
external opening just above the brain. In the abdominal region 
there is no dorsal blood vessel. It seems to be replaced by a 
sinus. The ventral blood vessel is very conspicuous. The in- 
testine is very much coiled. This is contrary to the usual type, 
which has a straight intestine. Probably this feature is due to 
the mode of life, as the worm is chiefly a vegetable feeder. The 
coils in the intestine give greater area for absorption. 
Evidences of regeneration are shown in a number of speci- 
mens. One large worm that had lost its greatly specialized 
branchie had started to grow a new crown. Other specimens 
that had a few of the branchial filaments torn away were re- 
