20 NAIURE 
[SEPTEMBER 7, 1916 
“ trout-flies,’ presented by Mr. Martin H. Mosely. 
The collection consists of a series of the natural in- 
sects that serve as food for trout and grayling (pre- 
served in formalin placed in shallow glass dishes), and 
along with them a series of the artificial insects which 
are made in imitation of the natural ones and used as 
bait by anglers. 
Tuere has been placed on exhibition in the Central 
Hall of the Natural History Museum, South Kensing- 
ton, a small series of specimens illustrating the natural 
history of the worm, Bilharzia (Schistosomum), that 
causes the disease of the bladder and rectum, known 
as bilharziosis, common in Africa, the West Indies, 
and Japan. Actual specimens are shown of the worms 
as they occur in the veins of the intestine, and examples 
are shown of pond-snails which are known to harbour 
the alternate generation of the worms. The life- 
history of the worm is explained by means of drawings 
of the egg and the sporocyst and cercaria stages, and 
photographs of bilharzia-infected: canals in Egypt, 
from Lieut.-Col. R. T. Leiper’s report of 1915, are 
exhibited to illustrate how the disease may be com- 
municated to human beings by bathing or standing in 
the infected water. 
In the Zoologist for August Dr. J. M. Dewar 
records a series of experiments on habit-formation in 
a queen wasp which had its nest at the end of a 
long tunnel opening into a disused rabbit burrow. 
The approach to the nest at the time of its dis- 
covery was made, not by the burrow, but through the 
tunnel. How she would behave when this tunnel 
was plugged was the task he set himself to discover. 
His observations lead him to the conclusion that “the 
learning of the wasp did not transcend the sensori- 
motor level, and that images or ideas were not 
elements essential to an explanation of the observed 
reactions.’’ He attaches, apparently, no importance 
to the fact that when the wasp first found the 
entrance plugged she gained access to the nest by the 
burrow, about 50 cm. below the tunnel,” and 
endeavoured to break away the plug from behind. 
Mr. R. Greenaway, in the Zoologist for August, 
comments at length on the inability of natural selec- 
tion to explain certain various phases in the evolu- 
tion of the protozoa. The protective coverings of 
‘Difflugia and Arcella among the Thecolobosa, or the 
addition of flagelle in the Flagellata, he argues, can- 
‘not be explained by natural selection, since this would 
demand similar armature and locomotory organs in 
~all the species of their respective types which-are 
now living side by side in the same environment. 
He concludes, therefore, that these differences are 
to be explained, at least in part, by ‘‘some form of 
the orthogenesis theory.” 
Ow1nc to the difficulty of obtaining material, the 
ovarian tissues of the Marsupialia have been very 
little studied. Thus the memoir’ which appears in 
the Quarterly Journal of Microscopical’ Science 
(No. 244, N.S., July), by Dr. C. H. O’Donoghue, will 
be extremely welcome. He describes at length the 
corporea lutea and the interstitial tissue of the ovary, 
more especially in regard to Phascolarctos, Tricho- 
surus, and Didelphys, thus supplementing his earlier 
observations on Perameles, Macropus, and Phasco- 
lomys. Perhaps the most important item in the pre- 
sent communication concerns the corpus luteum of 
*Phascolarctos, which remains as a hollow cavity 
throughout the period of pregnancy, and which during 
the time that the embryo is in the uterus is quite 
unlike the corpus in any other known marsupial, or. 
indeed, that of any other mammal. As a result of 
NO. 2445, VOL. 98] 
his investigations, the author is able to show that 
the corpus luteum of the marsupial and the eutherian 
are indistinguishable, thus directly contradicting the 
statements made on this subject by Fraenkel and 
Cohn, and repeated without criticism by Van der 
Stricht. . 
In Memoirs of the Geological Survey of New South 
Wales, Ethnological Series, No. 2, Mr. R. Etheridge, 
curator of the Australian Museum, Sydney, discusses 
the origin of the warrigal (Canis dingo), the name 
“dingo” being a contemptuous term applied by the 
aborigines to the white man’s cur. He reviews the 
evidence collected by. Sir F. McCoy and Mr. G. Krefft, 
who found its remains associated with a fauna now 
extinct. Mr. Etheridge adds to this that he 
thinks he has identified teeth of a dog somewhat 
larger than the warrigal among a quantity of jaw 
bones and loose teeth found in the Wellington Cave. 
He leaves the question of the origin and date of intro- 
duction in doubt, but the evidence here collected does 
not seem to conflict with the view that it was like the 
Indian pariah dog, and was brought by emigrants 
from the Malay region. 
THE report on the investigation of rivers undertaken 
by the Royal and Royal Geographical Societies has 
been published by the latter society. The investiga- 
tion, which was begun in 1906, had in view the exam- 
ination of certain rivers in England and Wales for the 
purpose of ascertaining the volume of discharge, the 
suspended and dissolved matter in wet and dry periods 
and the total for the year, the erosion of the surface 
of the basin, the rainfall in each basin, and the extent 
occupied by calcareous and non-calcareous, and by 
pervious and impervious formations. The rivers 
selected for examination were the Exe, the Medway, 
and the Severn. These were selected as river basins 
representative of different geological conditions. Cir- 
cumstances prevented the inclusion of the Salisbury 
Avon as a typical chalk river. The report is the work 
of various authors, including Dr. Aubrey Strahan, Mr. 
N. F.. Mackenzie, Dr. H. Ro@Mily and Dr: \joss 
Owens. Attention was directed to the desirability of 
such investigations by the recent report of the Royal 
Commission on Canals and Inland Navigation, but 
the work requires to be carried on systematically 
throughout the country. The present report serves to 
indicate the value of such a survey of our water re- 
sources, and the lines on which it should be conducted. 
In the Geographical Review for July (vol. ii., No. 1) 
there is a paper by Messrs. W. G. Reed and H. R. 
Tolley, of the U.S. Department of Agriculture, on 
“Weather as a Business Risk in Farming.” Climatic 
data expressed in averages afford a basis for deter- 
mining the general character of a region, but the 
farmer requires to know the frequency or magnitude 
of departures from the average. Late spring and early 
autumn frosts do great harm to crops. The statement 
of the extreme dates of these frosts is of doubtful 
value in the determination of the risk of damage, as 
it is based on single occurrences. The authors 
have calculated the standard deviation from the aver- 
age date of the last and first killins frosts, in spring 
and autumn respectively, and from this the frost risk 
may be computed. In two maps of the United States 
the standard deviations of dates of the last and first 
frosts are given as accurately as available data permit. 
INVESTIGATIONS of the meteorology of the upper air 
were begun in 191% at Melbourne. Rubber balloons 
were used, each with a meteorograph attached to a 
bamboo ‘‘spider."’ The work had not progressed far 
when the war interfered with its continuation. Mr. 
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