726 
COLOUR VISION AMONG CRUSTACEA. 
\WHETHER the lower animals have colour-percep- 
tion is a question that has long been discussed 
without conclusive evidence being forthcoming. Paul 
Bert and the late Lord Avebury may be cited amongst 
those who claimed by their experiments proof of a 
colour-sense in Daphnia, whilst other investigators, 
among the most recent being C. Hess, conclude that 
what appear to us as colours are to these lower 
Crustacea only degrees of brightness; that, in fact, 
these animals are in the position of a colour-blind man, 
and choose what are to him and them the brightest 
part of the spectrum. 
A recent issue of the Biologisches Centralblatt 
(vol. xxxiii., No. 9, 1913) contains an interesting and 
careful piece of experimental evidence on the behaviour 
of Daphnia and of Artemia to white and to mono- ! 
chromatic light. By the aid of a specially devised 
mode of illumination (a 1co candle Osram lamp and 
fluid light-filters or coloured glass screens) Dr. von 
Fritsch and Herr Rupelwieser have been able to make 
a more critical test of the responses of these Crustacea 
than was possible to most of their predecessors in this 
line of research. Working with white light (whether 
vertically or horizontally) these authors find that 
Daphnia remains evenly distributed under the influence 
of a medium light-intensity, but that it moves away 
from the source of light if the brightness of this is 
raised, and towards the light if the intensity is 
lowered. In this respect the work of the authors 
merely confirms similar observations already published. 
If now a blue screen be interposed the Daphnia, in 
spite of the lowered intensity, move away from the 
light. On the other hand, if a yellow screen is used 
the Daphnia move towards the light, although its 
intensity is greater and is such as would ordinarily 
induce a negative reaction. On these and other 
grounds the authors conclude that Daphnia has a 
colour-sense and not merely a perception of varying 
degrees of light intensity. Red, yellow, and green 
rays attract Daphnia; blue-green, blue and violet rays 
repel Daphnia. } ; 
The whole question has been dealt with more fully 
by the late Lord Avebury in his ‘Senses of Animals” 
(International Science Series, vol. Ixv., 1889) than the 
German authors give that distinguished naturalist 
credit for, and indeed they refer only to his earlier 
paper (1881). Both the German and the English 
authors arrive at similar conclusions, though Lord 
Avebury used a method of choice which was not 
employed by these most recent workers. 
One further point of interest is the varying degrees 
of response given by strains of the same species and 
of different species of Daphnia. For example, in test- 
ing the effects of coloured light upon the eye, a very 
definite response was at first found to occur in red 
light, and quite another in blue light; but when the 
observers tried to repeat this effect on another batch 
of Daphnia, they were unsuccessful in obtaining a 
strain which responded so well as the first, until after 
six months’ trials. Daphnia magna was found to 
give more consistent results than the common Daphnia 
pulex. RB. WG. 
ORNITHOLOGICAL NOTES. 
T the conclusion of a note on the food and feeding 
habits of the pheasant, published in the Journal of 
the Land Agents’ Society for December, 1913, Mr. W. E. 
Collinge states that the greater portion of the food of 
these birds consists of injurious insects and the seeds 
of weeds, the statement being based on the examina- 
tion of the contents of the crops and stomachs of no 
NO. 2313, VOL. 92] 
NATURE. 
[FEBRUARY 26, 1914 
fewer than 183 birds. Pheasants daily wander over 
large areas of land in search of food, and—altogether — 
apart from their value as game*merit protection on the 
part of all persons interested in agriculture. Although 
they -occasionally snip the leaves of root crops, 
especially in very dry weather, most of the damage 
of this nature laid to their charge is really caused by 
wood-pigeons. Q ? 
The difficult question as to whether * willow-tits,” 
as typified by Parus borealis, are really entitled to 
specific. distinction from ‘‘marsh-tits”’ (P. palustris), 
is discussed by Mr. Collingwood Ingram in The 
Zoologist for November, 1913, in connection with 
their respective French representatives. Provision- 
ally, the author considers it expedient to recog- 
nise this distinction, the marsh-tits being characterised 
by the steely-blue sheen on the crown, whereas in 
the willow-tits this is replaced by dull brownish or 
sooty black. 
The list of casual visitors to the British Isles has 
been augmented by the capture on October 3, 1913, 
of a specimen of the dusky warbler (Phylloscopus 
fuscatus) on Auskerry, in the Orkneys. The capture 
was recorded by Mr. Eagle Clarke in the Scottish 
Naturalist for the same year (pp. 271-3), and is more 
fully noticed in British Birds for January, 1914 
(pp. 220-3). The species breeds in eastern Siberia, and 
visits southern China, northern India, Burma, &c., in 
winter. 
In British Birds for December last Mr. G. R. Hum- 
phreys records the breeding of the rosy tern, Sterna 
dougalli, during the past summer in Ireland, where 
these birds have hitherto been supposed to be ex- 
tremely rare. In the breeding-place referred to by the 
author they were, however, met with in comparatively 
large numbers. The identification of the species is 
based on the examination of the parent birds with 
field-glasses, and on the colouring of the nestlings— 
notably of the legs—which is stated to be very 
markedly distinct from that of other terns at the 
same age. 
Further particulars with regard to the number of 
birds “ringed” during the past season in this country 
and records of their recapture are given by Mr. H. F. 
Witherby in the above-mentioned issue of British 
Birds. \ The total number is 14,843, against 11,483 
in 1912, and 2171 in 1909. The present percentage of 
recaptures (Mr. Witherby uses the word ‘recoveries,’ 
which suggests a meaning different from the one in- 
tended) is 3-3 per cent., on a total of more than 30,000; 
but as many of such recaptured birds afford no data 
of any importance, the percentage yielding informa- 
tion of scientific value falls short of three. 
To vol. xxxv. (pp. 209-23) of Notes from the Leyden 
Museum, Dr. E. D. van Oort communicates further 
particulars with regard to the recapture of birds ringed 
in Holland. Perhaps the most interesting items relate 
to a couple of spoonbills, one of which was shot in th 
Azores and the other in Portugal. 4 
The bird-life of the coast in the neighbourhood of 
Bergen forms the subject of an article, illustrated by 
very interesting photographs of nests and nesting- 
sites, by Mr. O. J. Lie-Pettersen, in the November 
number of Naturen. ’ 
Bird-Lore for November and December, 1913, is a 
highly attractive issue of an ever-popular journal, 
the two coloured plates of well-known American birds 
being well worth the price of the whole part. An 
editorial article alludes to the striking advances which 
have been made in the protection of American birds 
during the past year, while other articles mention th 
work done by the various Audabon societies, these 
being supplemented by the reports of local agents. — 
A remarkable difference in the plumage of male 
