Tube-building Habits of Terebella littoralis. By A. T. Watson. 687 
small stones, &c., are collected by tbe tentacles, and in the accom- 
panying drawings are shown travelling towards the prostomium. 
Some of the tentacles are quite short, and it is evidently their duty, 
when material is brought within their range by the others, to transfer 
it to the prostomium, which organ stretches up in a most eager 
manner to receive it, bending expectantly towards the tentacles, and 
turning now this way and now that until satisfied, reminding one of 
the action of an elephant’s trunk. This attitude is shown in the 
lateral view, fig. 2. When the material reaches the prostomium it 
is quickly rolled over within the mouth and covered with a white 
transparent cement ; the animal then bends over and deposits it upon 
the free edge of the tube, as shown in fig. 3, immediately after which 
it holds up its lips for a further supply. 
This operation may be watched for long periods together, but the 
observation of how the sandy fringe is built is a most difficult matter, 
and was only attained after about fourteen days of almost constant 
watching. In building the body of the tube the sand is deposited, some- 
times grain by grain, at other times several grains at once, and during 
the work the body of the worm is usually well within the tube, the fore 
part protruded only just far enough to work comfortably, the lips 
constantly receiving new material and placing it, as received , upon 
the growing edge of the tube ; but in building the sandy branching 
filaments a different method is pursued. A moderately large grain of 
sand is first laid as a foundation stone ; then the creature usually 
retires into its tube, and the tentacles collect and carry down to it a 
large supply of grains of sand, which is all received by the lips, and 
no doubt duly coated with the secreted cement. The animal now 
slowly emerges, and lays first one grain upon the foundation stone ; 
then, whilst still holding this with the lower portion of its lip, it 
forces a second grain, out of the supply in its mouth, above the first, 
through the upper portion of its lip. It then slides the whole lip 
upward to the second grain, which it holds as before, passing forward 
above it a third grain, and so on until the whole supply is exhausted, 
the worm keeping hold with its lip all the time, and withdrawing at 
lightning speed as soon as the last grain is attached, the whole opera- 
tion occupying, in the cases I observed, from 5 to 10 seconds only. 
The straightness of the filament is secured by the above means com- 
bined with a very steady and gradual advance of the body of the worm 
as each grain is added. When the top grain is laid the creature has 
often emerged so far that the whole three pairs of branchiae are 
outside the tube. This advance is of course produced by the setae 
pushing against the sides of the tube, whilst steadiness is secured by 
the hold which the uncini have upon its membrane-like lining. 
Figs. 4 and 5 will make the above description intelligible. 
Fig. 4 is a front view, showing the prostomium, as temporarily a 
hood -shaped organ, clasping with the lower portion of its lip the 
second of a series of grains which it is fixing, whilst a third grain is 
3 c 2 
