1885. | Zoölogy. 511 
cavity, and which is made up of a number of separate tubes; a 
small coiled portion was found lying in the cloaca as if ready for 
ejection. A small piece of a tube, measuring only 2.5™™ was 
found even after twenty years’ immersion in spirit, to be capable 
of extension to twelve times its own length; while, when treated 
with water, the attenuated thread swells up to seven times its own 
breadth. “We can thus understand that an animal at whom 
these threads are thrown should, as it attempts to escape, lengthen 
the threads which, at the same time, coming into contact with the 
water, would be swollen out transversely as they were extended 
longitudinally.” Professor Bell thinks that the observations con- 
firm the view of Semper as to the protective or offensive charac- 
ter of these organs, which, by Jager and most later anatomists, 
have been thought to be renal in function. 
In a subsequent note Professor Bell states that six threads, any 
one of which was only barely visible, were capable of supporting 
a weight of nearly a thousand grains; and quotes a letter from a 
correspondent to say that the black holothurians near Porto-Fino, 
emit a tangled mass of white threads so sticky and in such quan- 
tity that it was difficult to free the hands from them.— Fournal 
of the Royal Microscopical Society, December, 188 4. 
EartTH-Worms.—An interesting paper on the habits of earth- 
worms in New Zealand is contributed to the New Zealand Insti- 
tute by Mr. A. T. Urquhart. The species are not named, but 
with such wonderful opportunities as Mr. Urquhart possesses for 
making a collection of these, may we hope that, in addition to his 
following out his observations as to their habits, he will also 
advance science by making a careful collection of the forms and 
placing them in the hands of some of the able naturalists of the 
Auckland Institute for description? It will be remembered that 
Darwin assumes that in old pastures there may be 26,886 worms 
where the return of worms was a blank, the walls were crow 
with worms. Asa result there was an average of eighteen worms 
per square foot, or 784,080 per acre. Although this average is 
very striking when compared with that of Hensen, it is worthy 
of note that the difference between the actual weight of the worms 
is not so marked. According to Hensen, his average of 53,767 
