PROCEEDINGS OF THE PERTHSHIRE SOCIETY OF NATURAL SCIENCE. 
209 
ample, a shake to the table or shelf on which the tanks 
staDd, or a tap on the vessel with the finger-nail, is enough 
to cause them all to disappear beneath the surface, from 
which, however, they emerge in less than a minute, and 
continue their regular wavy motion. In the laboratory 
tank or dish it is just as difficult to isolate and get out a 
single specimen as it was to get them from the pond. I 
have often got an individual into the end of a glass 
dipping-rod, but on withdrawing the finger from the other 
end of the rod, instead of the worm being “sucked” into 
the tube, it dives instantly into its hole and declines to be 
captured in that way. To isolate specimens it is necessary 
to wash the mud away under a continuous flow of water, 
and leave them high and dry on a plate or shallow dish. 
They can then be examined under chloroform in the usual 
manner with the live-box or the compressorium. 
In this short paper I do not propose to treat of their 
anatomy at all, but to confine my brief remarks to one or 
two additional points in their habits. The worm has been 
described very fully by many observers. By Bonnet, who 
first noticed it; by Claparade, who is facile princeps in all 
researches on worms ; by D’Udekem, who has written a 
splendid monograph of this species in the Transactions of 
the Royal Society of Belgium, while several of our own 
naturalists—Ray Lankester and M‘Intosh—have added to 
what was already known about its anatomy and its repro¬ 
duction. 
In order that you may understand the diagrams, I will 
merely remark that it varies in length from one to three 
inches; that in thickness it is about l-12th of an inch in 
diameter, that its blood is red, and its intestines appear 
through its transparent skin of a rich olive green or brown 
colour; and that its several segments bear four rows of 
setae,—“ feet " we call them in familiar language,—by 
means of which it moves so briskly in the medium in which 
it lives. 
I will also add that in your own streams and ponds it 
is equally common as with us, but because the bottoms of 
your ponds and streams are darker in colour than our ooli¬ 
tic mud, the contrast in colour between the worm and its sur¬ 
roundings is not so striking. Still you may find it in 
myriads by careful search. The first time I ever made its 
acquaintance was in a Scottish stream where it occurred 
on a narrow strip of the bed on one side for more than half 
a-mile in length. 
I have kept this Tubifex in my laboratory tanks for more 
than three years, and have thus had very good opportuni¬ 
ties of studying it. My observations are still going on, 
and I do not yet know so much about it as I should like to 
do, but I think I have settled one point in its habits which 
may interest you. Bonnet, who first studied it, said it 
made tubes in the sand of streams in which it lived. La¬ 
marck gave it the name of “Tube-fashioner” from this habit. 
D’Udekem says they inhabit the bottoms of brooks; prefer 
running water and a sandy bottom; construct tubes, in which 
they hide entirely with great rapidity. MTntosh repeats 
this, and adds that they occur sometimes under stones in 
very damp situations, makingpermanent burrows for them¬ 
selves, as we see earthworms do under similar circumstances. 
Now I came to the conclusion some years ago that 
Tubifex rivulorum did not make tubes at all, and my 
observations on it since then, made almost daily during the 
spring and summer on specimens kept under the most 
favourable conditions, in tanks with stagnant water and in 
tanks with running water, have led to a confirmation of 
that view. Whenever in our pools we stir up the mud 
with a spade or a stick, we should undoubtedly destroy the 
tubes of the worm if there were any—but what do we find ? 
However vigorously we may rake the mud, a few minutes 
is sufficient lapse of time to enable the worm to emerge 
from the mud and appear as though nothing whatever had 
happened. On washing out the individual worm in the 
manner already described no trace whatever of the 
slenderest of tubes is to be found. What then has led 
previous observers to fancy that this little annelid was a 
tube-maker? I have forwarded a second diagram, which 
has been drawn by one of my students partly from a little 
sketch by D’Udekem, but also from directions suggested 
by the aspect of the living worm in confinement, and it 
will serve to explain, I think, one reason for the supposition 
that it is a tube-maker. You notice a number of worms 
projecting from a surface of vegetable matter and mud, 
represented as moving from side to side. Around each 
worm, just where it leaves the mud, is a little hollow cone 
of decayed vegetable matter almost like an inverted fun¬ 
nel, and this you might at first sight take for a tube. It 
is probably just such an appearance as led Bonnet to say 
it was a tube. But if you were to violently agitate the 
vessel in which these cones are formed,—even turn it up¬ 
side down (if it be a bottle) and give it a good shaking,— 
you will destroy all the inverted funnels, you may reduce 
everything but the worms themselves to impalpable mud 
and debris, but as soon as the water clears again you will 
remark that the worms have survived the process, and 
have quietly resumed their habit of waving about half in 
and half out of the mud. What is more important, how¬ 
ever, you will notice that the formation of these little 
cones is again proceediug, and that it i3 due to the slowly- 
falling particles of vegetable and other matter which 
arrange themselves around the moving worm. I have 
