January 2, 1882.] THE TROPICAL AGRICULTURIST. 
S 7 1 
than one occasion used my influence to save this re- 
markable tree. 
The calabash plant of (he Wcsb Indies, Crcscentia 
Cujete, which was introduced to Ceylon more than 
20 years ago, and is now quite common about Colombo, 
is a close ally of the Kegelia : indeed they were 
formerly included in a eeparato family, Orescmtiaceae 
so named from tho former genus, but thoy are now 
included in Bignoniaccac, (See notice of Crescenlia 
Cujde in note /' at bottom of p. 208 of "Ferguson's 
Directory " for 1863.) 
Mr. A. M. Ferguson when travelling in Ceylon or 
elsewhere, never lost the chance of collecting speci- 
mens in flower or fruit of any plants which struck 
him as being remarkable or ornamental, with notes on 
them, and his long residence in Ceylon has enabled 
him to learn a considerable number of the names of 
plants ; but without a list of the plants, introduced 
and naturalized in Ceylon, and an idea of what they arc, 
he and others are likely to bring specimens of plants 
we already possess. 
Mr. Morris's catalogue was the first attempt made 
to enumerate tho foreign plants growing in Ceylon, 
but a second edition or catalogue on another plan is 
much wanted, to enablo parties deeply interested in 
the introduction of useful and ornamental plants toavoid 
the useless expense of introducing plants already in 
the island, many of them here since the times of the 
Portuguese, Dutch and Knglish, viz., 1505 to 1G56, 
1656 to 1795, and 171'5 to 18S1. It is perhaps adding 
a few straws to Dr. Trimen's burthen to ask him to 
mako such a catalogue in the midst of his multi- 
farious duties, but I feel sure such a catalogue would 
be very valuable, and much appreciated by a large 
number of people resident in Ceylon and elsewhere 
interested in the island and its productions introduced 
and indigenous. I believe nearly every other colony 
except Ceylon has issued such a catalogue. — W. F. 
MR. DARWIN ON EARTH-WORMS.* 
At first sight, the subject of Mr. Darwin's new book 
seems to promise less of interest to the general reader 
than almost any among tho series of minute and 
patient monographs which have followed up the 
epoch-making publication of the "Origin of Ppecies." 
But tho fact in, Mr. Darwin's skill lies most of all 
in just such surprises as that which he gives us in 
this delightful little volume. He takes up some 
unpromising and seemingly dull study— the growth 
of coral reefs, the slow movcnionts of climbing plants, 
the effects of cross-fertilization — and in his wonder- 
working hands tho mass of dry detail becomes quick- 
ened as if by magic into a liviug romance, full of 
vivid reality and instinct with evolutionary plot- 
iotercst of tho most fascinating sort. Something of 
the same kind he has now done with tho common 
earthworm. In tho eyes of most men— nay, even of 
most naturalists— the earthworm is a mere blind, 
dumb, senseless, and unpleasantly slimy annelid. Mr. 
Darwin undertakes to rehabilitate his character, and 
the earthworm steps forth at once as an intelligent 
and beneficent personage, a worker of vast geologi- 
cal changes, a planer down of mountain sides, a 
creator of fertile alluvial corulands, a friend of man 
in his agricultural operations, and an archaeological, 
though unconscious, ally of tho Socioty for tho Pre- 
servation of Ancient Monuments. 
Tho surfaeo of the eurth in all moderately humid 
countries h eovcred in .1 d< |>th of .some inches by a 
rich layer of blackish vegetable mould, composod of 
» "The Komi itlon of \ • etahln Mould throu ;li tin" 
Action of Worms; with obaervationi on their habits." 
By ('hath. Dai win, L.L.D., K U.S. (London: .John 
Murray. 18S1.) 
L46 
uniformly fine and small particles. The part which 
earthworms have borne in producing and renewing this 
all-important coat of fruitful soil forms the main sub- 
ject of Mr. Darwin's investigation. As long ago as 1837 
his attention bad been called to the matter in hand by 
Mr. Wedgwood, who suggested to him that the tendency 
of marl, cinders, or pebbles strewn over meadows to 
"work themselves downwards," as the farmers phrase 
it, was really due to the large quantity of fine earth 
brought to the surface by worms in the form of cast- 
ings. Mr. Darwin has followed up his inquiries with 
his usual minute experimental care, the result being the 
little work now before us. But as the world at large ha 
not kept and watched tame worms with the same 
assiduity as our great naturalist himself, he is kind 
enough to preface his remarks with a full account of 
the habits and manners of the animals which makes up 
by no means the least interesting part of his book. 
Earthworms belong to a few genera, externally closely 
resembling one another, and distributed apparently 
over the whole world. They abound on bare chalk 
downs and in London parks ; they inhabit the most 
isolated islands, and they have by some mysterious 
means found their way even to Kerguelcn Land in 1 he 
Antarctic Ocean. In (heir habits they arc nocturnal, 
remaining in their burrows during the day, and only 
coming out to feed at nightfall. They lie, however, 
close to the mouth of the burrows, apparently for the 
sake of warmth, and are thus devoured in large num- 
bers by birds. The most interesting point in their 
internal structure is their possession of gizzards, in 
which they triturate their food with the aid of small 
stones, a function which has important bearings on the 
production of mould. On their senses and intelligence 
Mr. Darwin made several curious and careful experi- 
ments. He found that, though they had no eyes the front 
part of the body, containing the cerebral ganglia, was 
slightly sensitive to light (a point of much lateral 
importance as bearing upon the evolution of special 
organs of sight), and that when the rays from a 
caudle were concentrated with a len3 npou what we 
may by courtesy call their heads, they "dashed like 
rabbits into their burrows." If, however, the heads 
were shaded and light cast on other parts of the body, 
they took no notice of it. This ability to distinguish 
between day and night doubtless serves to protect 
theai from diurnal animals which prey upon them. 
On the other hand, worms are absolutely deaf, and 
when Mr. Darwin played the piano to them, they 
obstinately rt-fused to listen to the music ; nor were 
they moved even by the strains of a metal whistle. 
By way of compensation they are actuely sensitive to 
jars, and retreated at once when their pot was actually 
placed on the piano and a note struck. Smell seems 
to be present, though feeble ; for while they took no 
notice of perfumes or of acetic acid, they quickly 
discovered bits of cabbage and onion buried iu the 
ground. Tasto they clearly possetscd, as they shewed 
a marked preference for green over red cabbage, and 
for celery over oither; and they distinguished in liko 
manner between tho leaves of different trees. But 
they are as omnivorous us man himself, greedily 
devouring meat ; and when Mr. Darwin fixed several 
pieces by long pins in their pots, they might be soon 
night after night half out of their burrows tugging at 
the bits of this rare delicacy. Iudced, so closely do 
they approach tho ljvel of humanity that they aro 
actually caunibals as well. 
Tho evidence of intelligence iu worms is slight ; but 
Mr. Darwin thinks sufficient. They drag leaves nr. 
their burrows (which aro regularly constructed nost*, 
with a chamber at tho bottom) party ns food, and 
partly to plug up tho mouth ; and Mr. Darwin 
noticed that the way in which they pulled down 
oveu unfamiliar or foreign leaves and triangles of papor 
so as to avoid mechanical difficulties was indicative 
