538 
there is now but little first-class timber remaining, save in very 
remote places. The botanical characters of this forest, which 
is everywhere evergreen, were given ; and the paper concluded 
with a few remarks on the coast flora, which is yery uniform 
throughout the tropical belt of the world. 
On ‘* Humboldtia laurifolia” as a Myrmecophilous Plant, by 
Prof. Bower.—It had been found that there were considerable 
numbers of plants in tropical countries which were pre-eminently 
associated with ants. The Italian botanist Picari propounded a 
general view with regard to the subject that the association was 
mutually advantageous to the ants and to the plants. He 
found that the plants gave shelter to the ants, and in certain 
cases supplied them with food. No one would deny the state- 
ment that the relation was advantageous to the ants themselves, 
but the converse case was not so clear. In some cases it had 
been found that the ants served to protect the plants, and drove 
off other insects. Picari also pointed out that in certain cases 
the plants derived nutriment from the excreta of the ants, but 
whether that was the case was a view open to considerable dis- 
cussion. He (Prof. Bower) had come to the conclusion that the 
ants derived all the benefit, and that there was no advantage to 
the plants. Not only were the ants provided with a capital 
lodging, but it might be fairly assumed that from the giands of 
the plants the insects derived food as well. 
On the Artificial Production of a Gilded Appearance in 
Chrysalises, by FE. B. Poulton.—The author remarked that 
some years ago Mr. T. W. Wood brought before the notice of 
the Entomological Society of London some proofs that certain 
chrysalises imitated the colour of the surfaces upon which they 
threw off their caterpillar skin. The intimation was received 
with some amount of credulity by leading entomologists, but 
evidently without sufficient reason, For some years the writer 
had been working upon the colour of caterpillars in relation to 
the colour of their surroundings, and he had shown that the 
colour could be modified in one generation by the alterations of 
their surroundings. It seemed certain that through some sensory 
surface, possibly the eye, caterpillars were affected by their 
external relations, and a corresponding effect was produced in 
colour. Mr. Wood’s experiment was but a special case of some 
general method of production. He explained the results by 
supposing that the moist surface of a fresh chrysalis was photo- 
graphically sensitive to the colour of surrounding surfaces. 
That appeared to be merely a metaphor, and was unsupported 
by proof. It was more probable that the colour was produced 
by the effect upon the caterpillar before it turned to the chrysalis. 
Experiments were therefore made by the writer to put the fact 
itself beyond dispute. That was done first by the use of caterpillars 
of the peacock butterfly and the common tortoiseshell butterfly. 
It was found that by allowing them to turn to chrysalises upon a 
white or a black screen very different results were produced. 
Those upon white paper were often brilliantly golden, although 
the chrysalises of the tortoiseshell were not quite so golden. 
Gilded specimens were sometimes found, but their appearances 
seemed to be produced as a disease. While that was the case 
of chrysalises found in the fields, the specimens experimented 
with by the writer were perfectly healthy, and produced healthy 
butterflies. He then saw that, although a white paper produced 
a golden appearance, a gilded surface would produce the 
same effect toa greater extent. That bore in a most important 
manner on the use of the metallic tints of many of the exposed 
chrysalises of butterflies: which were thus seen to have harmon- 
ised with some metallic surroundings. The next point was to 
ascertain the period during which the caterpillar was sensitive to 
the colour of the surrounding surfaces, and the nature of the 
surface which was affected. The former end was achieved by 
carefully watching the caterpillars between the time at which 
they ceased feeding and that at which they turned to chrysalises. 
It was found that they were sensitive for many hours, even more 
than a day, before the change took place. The other object 
was attained by placing the larvee suspended downwards for ten 
or twelve hours before the change took place ina tube, of which 
the upper part was golden and the lower black, the two being 
separated by a perforated disk. The caterpillar’s head was 
turned round so that it could not see through the aperture, and 
the result showed that the chrysalises were the colour of the 
chamber in which the head was placed. Hence it seemed that 
the sensory surface must have existed upon that area, The full 
results, however, had not yet been obtained. 
The Nervous System of Sponges, by Dr. R. von Lendenfeld.— 
The author gives an account of his discoveries on this subject up 
to date. Sensitive and ganglia cells have been observed by him 
NAT ORE 
4 
in a good number of sponges. 
Their locality varies, their shape 
is constant. 
They are mesodermal, and appear to preside over 
| | 
[ Sept. 30, 1886, 
} 
) 
4 
the movements of the membranes and pore-sieves, and so regu- 
late the water current. The great difference between sponges 
and higher ccelenterates is, that in the former the most important 
organs are mesodermal, whilst in the latter they are ecto- or 
ento-dermal. He divides the type Ccelenterata accordingly into 
Calenterata Mesodermalia, or sponges, and Calenterata Epithe- 
/aria or Cnidaria, as Lulitypes. 
The Function of Nettle-Cells, by Dr. R. von Lendenfeld.— 
The author gives a detailed account of the structure of the nettle- 
cells, or cnidoblasts, and discusses some biological facts regard- 
ing their function. He comes to the conclusion that the nettle- 
cells are exploded by direct reflex action when the cnidocil is 
touched, but that the animal can counteract this reflex action by 
a centrifugally acting nervous irritation in a similar manner as 
reflex actions are controlled by higher nervous centres in man. 
Note on the Floral Symmetry of the Genus Cypripedium, by 
Dr. Maxwell T. Masters, F.R.S.—In this note the author 
adverts to so much of the normal structure of Orchids in general, 
and of Cypripedium in particular, as is necessary for the elucida- 
tion of his subject, and proceeds to describe a case of regular 
peloria in Cypripedium caudatum, which shows a reversion to 
the typical form of Orchids, and goes to prove that the so-called 
genus Uropedium is only a pelorian form of Cypripedium. The 
construction of the andrcecium in these plants is then alluded to, 
and illustrations given of all intermediate stages from monandry 
to hexandry. The frequently observed tendencies to a dimerous 
condition, and to the development of the inner row of stamens, 
are alluded to, and the significance of these changes pointed out. 
| 
The morphological changes consequent upon hybridisation, and 
the inferences to be derived from them, are passed under review. 
The paper concludes with a general summary of the teratological 
changes observed in the tribe Cypripediez. 
Votes on Australian Calenterales, by Dr. von Lendenfeld.— 
The author describes the extraordinary mode of development of 
Phyllorhiza punctata, a rhizostomous Medusa discovered by him 
in Port Jackson. The Ephyra has eight, the next stage twenty- 
four, the next sixteen, and the adult again eight marginal 
bodies. If the umbrella margin is injured and newly formed, 
marginal bodies appear between a// the newly-formed flaps. 
Further, the migrations of Cyambessa masaica at the breeding — 
time are described. This and other species of that genus of 
rhizostomous Medusz migrate far up the rivers, like the salmon, 
to deposit their young. A remarkable change in the colour of 
C. masaica, which has taken place in Port Jackson since the 
observations of Huxley about fifty years ago, is described. A 
new variety, which is brown, seems to have been produced or 
to have immigrated and superseded the 4/we form, which was 
observed by Huxley and others in that locality. In Port Phlilip 
the blue variety is still found. The author has found in examin- 
ing the lower freshwater animals that the freshwater Hydroids 
and Sponges, as also the freshwater Khizopoda of Australia, are 
very similar to the European, whilst the warize species of these 
groups differ very much in the two localities. He concludes 
that these freshwater forms are very old and conservative, and 
may be supposed to be the unchanged offspring of old ancestral 
forms, as such possessing particular systematic importance. 
Bugio; the Biological Relations of an Atlantic Rock, by 
Michael C. Grabham, M.D., F.G.S., F.R.C.P.—Region 
almost unknown, but interesting as being typical of flora distri- 
bution, and of variation in isolation, Author proposed to illus- 
trate present knowledge by reference to prominent forms, 
animal and vegetable, existing at Bugio, the most unknown of 
the Dezerta islets. 
Dezerta.—Physical characters: Foundation on a narrow 
ledge ; dimensions never much greater ; no evidence of ancient 
contact ; not survivals of an ancient continent, but islands in a 
Miocene sea, deriving their first colonists from Miocene Europe. 
Description of Bugio.—Difficulty of access ; central volcanic 
dyke ; large proportion of tufas ; no sections of old river-beds 
or surface obliterations ; summit showed deep clay-beds and 
surface deposits of calcareous sand and earth. 
Flova.—Uow related to Madeira; arbitrary distribution ; 
absence of easily wafted forms ; Senecio ztncrassatus, Madeiran 
and Canarian varieties ; Zchtum fastuosuem, maritime form of ; 
hybrid with Z&, s¢mp/ex, remarkable perpetuation of perennial 
growth, and other changes ; several instances of fitful distribu- 
tion ; Chrysanthemum dematomma, a distinct and only species ; 
remarks on cognate Madeira forms ; Monizia edulis, Dezertan, 
Salvagic, and Madeiran examples ; Miocene origin of. 
