182 
SUMMARY OP CURRENT RESEARCHES RELATINO TO 
caused the death of a goura. The animal was white, 2-3 mm. in length, 
cylindrical in shape, with four pairs of appendages, but without any 
mouth-organs, in fact without any mouth. The form of the body sug- 
gests Phytoptus and Demodex, the teet and the epimera remind one of 
Analges. As feathers and epidermis were uninjured the “mite” can- 
not have made its way in from outside. 
€. Crustacea. 
Influence of Light on Coloration of Crustaceans.* — M. A. E. 
Malard points out that the influence of light on the coloration of Crus- 
taceans, which is enormous, may be effected in two different ways; 
chemically, that is by the modification of a pigment under the direct 
influence of light, or physiologically by the action of chromatoblasts 
working indirectly under the influence of light, and by the intervention 
of a sort of reflex process which actually originates from the eyes of the 
animal. Recalling the observations of many naturalists and his own, 
the author concludes that concealment by isochromatic adaptation seems 
to be very common among Crustacea, and that albinism is only a par- 
ticular case of a very much more general phenomenon of chromatic 
adaptation to environment. 
Ganglionic Lamina of Palinurus.f — Under the general title of a 
contribution to the histology of the nervous system of Invertebrates, 
M. H. Viallanes here deals with one subject only ; he finds it necessary 
to take parts in detail, as he is of opinion that Dr. Nansen has general- 
ized too widely from insufficient data. The lamina here dealt with 
forms a delicate hemispheral cup between the basal membrane of the 
eye and the external medullary mass of the optic ganglion. He finds it 
to be composed of a large number of small organs, each of which cor- 
responds to an ommatidium, and which therefore he designates as 
“ neurommatidia.” This last is a mass of protoplasm of areolar struc- 
ture, and has the same histo-chemical reactions as the protoplasm of the 
ganglionic cells ; it is traversed by seven cylinder-axes which come from 
the corresponding ommatidium, which pass on to the deeper parts of the 
optic ganglia. Between the neurommatidia, but not uniting directly with 
them, there circulate the branches of a rich nervous plexus ; from this 
fibres are given off which pass to the deeper centres. 
With regard to the function of these parts the author suggests that 
the seven cylinder-axes which traverse the neurommatidium act by 
induction on the protoplasmic substance which forms it. The substance 
of this last acts in its turn, by induction, on the fibres of the plexus, and 
thus gives rise to nerve-currents. 
Absorption in the Crayfish. J — M. C. de Saint-Hilaire finds that the 
pancreas (so-called liver of earlier authors) of the Crayfish has the 
function of excreting certain anilin colours, when these are injected 
into the blood. This is probably effected by the tubes of the pancreas 
absorbing the colouring matters by their blind ends ; after this absorp- 
* Bull. Soc. Philom. Paris, iv. (1892) pp. 24-30. See Ann. and Mag. Nat. Hist., 
xi. (1893) pp. 142-9. f Ann. Sci. Nat., xiii. (1892) pp. 385-98 (1 pi.). 
X Bull. Ac. Roy. Belgique, lxii. (1892) pp. 506-16. 
