Tube-building Habits of Terebella littoralis. By A. T. Watson. 689 
From a sanitary point of view these fringes might be regarded as 
likely to hinder the free expulsion of refuse matter, but this is not the 
case. Such matter is thrown with some force quite clear of the tube 
by the animal doubling itself into a U-shape, and forcing the long 
narrow posterior portion of its body well out of the mouth of the tube. 
I may remark that the semicircular flaps appear to he formed 
after the fringe by a process of shelly plating filling up the spaces 
between the filaments. Usually the fringed summit only of the tube 
projects above the sand, but the portion buried is sometimes of very 
great length. This summer I obtained tubes no less than 19 in. long, 
and I am not sure that even then the whole length was secured, as it 
is exceedingly difficult to dig them unbroken out of the loose wet sand 
into which they descend almost vertically. 
