28 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
following. Lankester and Cliatin were in error in believing that the 
secreting cells or macroblasts contained the green pigment. These cells 
function as JBecherzellen , secreting a substance physically, but not chemi- 
cally like mucus. The opinion that the green coloration of the palps 
and gills is due to a transport of material from the gut by means of the 
amcebocytes of the blood is completely erroneous. De Bruyne’s facts, 
for instance, deal with pathological conditions. The presence or absence 
of the green diatom Navicula is of little moment in coloration. The 
green substance, or marennine, is a product of metabolism, and may be 
formed in a great variety of epithelial cells, though not in the BecJier- 
zellen and claviform cells. It is an organic substance, of peculiar com- 
position, with iron as one of its principal elements. It is perhaps a 
nutritive substance, and is carried by amoebocytes from epithelial cells 
to the liver. One of the results of the author’s studies is to show that 
the amcebocytes are of essential importance in nutritive transport. 
Arthropoda, 
a. Insecta. 
Colour- Variation in the Vanessas.* — Dr. F. Urcch adopts the view, 
especially emphasised by Eimer, that organisms are to be regarded as 
very complex material systems, and that therefore any change at one 
point must be accompanied by compensatory changes at other points. This 
view he illustrates by a tabular survey of the artificially produced 
colour-variations in Vanessa. His conclusions are — (a) that in ontogeny 
the effect of warmth is to deepen the tint of pigmentary colours by a 
concentration of the pigment at special points, rather than by an actual 
increase in amount ; and ( b ) that the continued action of heat through- 
out many generations produces an increase in amount of pigment and a 
deepening of tint, and of cold, a decrease in amount and a diminution of 
intensity of tint. The increase in amount may manifest itself either 
directly or indirectly as an increased complexity of chemical structure. 
In other words, colour-changes occurring during ontogeny are to be 
regarded merely as new positions of equilibrium ; but an increased 
temperature acting through many generations may lead to absorption of 
energy, and so to actual increase of pigment production. 
In estimating colour-change Urech emphasises the importance of 
realising that optical colours usually occur in non-pigmented scales, so 
that an increase in blue or violet (optical) colours may be due to an 
actual decrease in the amount of pigment present. If this be kept in 
mind, he is of opinion that almost all artificially produced colour- 
changes in the Vanessae mny be explained as correlated or compensatory 
changes. 
The paper contains also some additional arguments in favour of the 
author’s view, that the progression of colours observable during develop- 
ment in the Vanessae is to be regarded as a case of recapitulation. 
Bag-Shelter of Larvae of Australian Moths.j — Mr. W. W. Froggatt 
states that, in many parts of the Australian bush, one frequently comes 
across brown, liver-coloured silken bags, of an irregular funnel shape, 
* Zool. Anzeig., xix. (1896) pp. 163-74, 177-85, 201-6. 
t Proc. Linn. Soc. New South Wales, xxi. (1896) pp. 258-60 (1 pi.). 
