688 
Analyses of Books. 
[November, 
the problem of artificial flight, the solution of which, prior to a 
total change in the moral condition of mankind, would, it seems 
to us, be the direst calamity conceivable. 
Mr. H. C. Russell, the Astronomer Royal for New South 
Wales, read a Memoir on a new form of ACtinometer, to show 
not only the hours when the Sun shines, but also the intensity 
of the heat. 
Mr. C. Moore, F.L.S., read Notes on the Genus Doryanthes, the 
“ Great Lily” of Australia, giving description of a new species. 
This plant, which grows to the height of 20 feet, is not a true 
lily, but an Amaryllis. It is not only remakable for the beauty 
of its red flowers, but yields a fibre remarkable for its tenacity 
and silky lustre. It can be obtained in threads 3 feet long, and 
can be produced to any extent. 
Mr. W. H. Caldwell, M.A., communicated a most important 
paper on the Development of the Monotremes and of the Cera- 
dolus. It is interesting to remember that this investigation was 
suggested to him by the late lamented Professor Balfour. He 
describes first the reproduction of the marsupials, now the cha- 
racteristic animals of Australia. The main difference between 
them and ordinary mammals is that in the latter the embryo 
before birth has no vascular attachment to the walls of the 
uterus. 
The Ceratodus is a representative of a series of animals once 
very numerous, but having now three living representatives 
only — the Ceratodus of Queensland, the Lepidosiren in the 
Amazon, and the Propterus found in certain African streams. 
These three animals possess gills, and have in their adult state 
the form of a fish, but they have also lungs. There is an indi- 
cation of two chambers in the heart, and of the presence of 
arterial blood. The egg of the Ceratodus undergoes a complete 
segmentation, like that of the kangaroo. 
The author’s most important discovery is that the Monotremes 
are reproduced by eggs, the Ornithorynchus laying two, and the 
Echidna only one. These eggs, like those of birds, and unlike 
the true mammalian ova, contain a large food yolk. Nevertheless 
both suckle their young. 
It is laughable to find that during the last few weeks before 
his Memoir was read Mr. Caldwell had received several letters 
denying that the Platypus laid eggs, and wanting to argue about 
it. Now, as he remarks, a fad may be disbelieved, but it cannot 
be argued about. 
