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takes to be vegetation. These canals are admittedly difficult 
to see. Indeed, Barnard, with the magnificent equipment at 
the Lick Observatory, has never been able to see them. It has 
been thought, therefore, by some, that they are of a subjective 
_ nature, due to an optical delusion under the strain of observation. 
Maunder, with a view to test this, set some model discs roughly 
representing Mars before some boys in Greenwich Hospital, who 
were told to draw what they believed they saw. He found that 
those who were at such distances as to see with difficulty drew lines 
across the surface, similar to the lines drawn by so may observers 
across the “‘seas’”’ of Mars, which did not exist in the models. 
Prof. Cassie concluded by saying that we have no evidence that 
the planet contains intelligent beings. 
On Friday, April 8th. Professor F. J. Edgeworth, M.A., 
D.C.L., a Vice-President, in the chair 
Mr. Macleod Yearsley F.R.C.S., F.Z.S., gave a lecture on 
‘« Hearing in Animals and Man.” The lecturer began by sketching © 
in outline the origin of the organs of special sense from the primitive 
- protozoon, which is sensitive all over, to the higher animals which 
have specialized organs and nervous systems for receiving, trans- 
mitting and interpreting sense stimuli. 
The auditory organ in its most elementary form consists of 
a small vesicle full of fluid. An auditory nerve terminates within 
this vesicle in special hair cells in contact with which are cal- 
careous particles termed otoliths. Upon this fundamental basis 
the hearing organs of nearly all animals are constructed with 
the addition of more or less accessory apparatus. 
Discussing the question whether the lower animals possess 
a sense of hearing, the lecturer argued that it would seem reason- 
able to suppose that those that have organs for producing sound are 
able to perceive sound. 
Mr. Macleod Yearsley described and showed drawings of the 
hearing organs in the coelenterata, annelida, mollusca, and echino- 
dermata. He also described the forms of auditory apparatus 
found in the arthropoda, referring especially to the crustacea and 
insecta. 
In vertebrates the simple otocyst becomes the more complex 
membranous labyrinth enclosed in the lateral wall of the skull. 
The lecturer led the audience through the changes of form of the 
labyrinth shown in fish, amphibian, reptile, bird and man. He also 
showed the differences in the internal and external accessory 
parts. He showed that the bird-like affinities of the monotreme 
or nithorhyncus extend to the anatomy of the ear. 
_ The working of the human auditory apparatus was discussed 
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