82 REPORT—1848. 
ramble into representations of climate in regions of depth. Thus we have the climate 
of a parallel represented in marine depths as in terrestrial elevation, and thus it ap- 
‘pears that density or depth is not so great an antagonist to the existence of animal 
life as is generally supposed. 
The greatest depth at which I have procured animal life is from 390 fathoms ; but 
I believe that it exists much lower, although the general character of the Aigean is to 
limit to 300 fathoms; but as in the deserts we have an oasis, so in the great depths 
of 300, 400, and perhaps 500 fathoms, we may have an oasis of animal life amidst the 
barren fields of yellow clay, dependent upon favourable and perhaps accidental condi- 
tions, such as the growth of nullipore, now found to be a vegetable instead of a coral, 
thus presenting prolific spots favourable for the existence and growth of animal life. 
These peculiar conditions of density and food develope necessarily a peculiar fauna, 
upon which climatal influence nevertheless stamps its characteristic forms through- 
out the species. 
Notice of an Observation at Bathealoa, Ceylon, on the Sounds emitted by 
Mollusca. By T. L. Taytor. 
“‘ There is a curious thing here which I don’t know whether you ever heard of. 
Going at night on the lake in the neighbourhood of the fort, one is struck by a loud 
musical noise proceeding from the bottom of the water. It is caused by multitudes 
of some animal inhabiting shells, I believe; at least the natives call them the ‘ Sing- 
ing Shells,’ and I have been shown what they said were those which made the noise. 
Some people doubt, however, whether it is these shells that sing, or some others, or 
fish of some kind. Whatever it be, I can answer for having heard the sounds re- 
peatedly, so distinctly too that you cannot help hearing them even when the oars 
and paddles are splashing, and the boat going fast through the water. The sounds 
are like those of an accordion or Aolian harp, guitar or such-like vibrating notes, 
and pitched in different keys.” 
Cases of impaired Vision in which Objects appear much smaller than natural. 
By A.Watrer, M.D 
This paper contained some observations of impaired vision in which the principal 
symptom consisted of an altered appreciation of the sizes of external objects. They 
were presented for the purpose of elucidating the action of the nerves and of the mind 
in the judgement of the dimensions of objects. In one case the illusion existed in 
one eye only, which perceived objects much smaller than the other. In other cases 
the illusion in both eyes was temporary, merely lasting for a few minutes at a time 
during the day, and then suddenly disappearing. 
On the Luminous Spectra excited by Pressure on the Retina and their appli- 
cation to the Diagnosis of the Affections of the Retina and its appendages. 
By A. Wauier, M.D. 
These observations relate to the luminous spectra which appear in the field of 
vision when the eyeball is compressed, or when the head has received a sharp blow, 
and in various other circumstances. After having described the discoveries of Sir 
Isaac Newton and others, the author goes on to relate his own observations, and 
finds that these spectra vary according to the part of the eyeball which is compressed. 
If compressed at the upper part, they appear to be most bright, and consist of seve-_ 
ral concentric rings alternately bright and dark. He shows that these spectra may 
be employed with great advantage as a means of discriminating the diseases of the 
retina and optic nerve from those which affect the crystalline lens, the iris, and the 
other parts in front of the retina. In amaurosis, glaucoma and other affections of 
the nervous parts, the spectra are found to become more faint in proportion as the 
nervous powers are injured, and are entirely absent when the visual powers are more 
deeply impaired. On the other hand, in those numerous affections of the eye where 
the rays of light can no longer form their images on the retina on account of the 
opacity of the parts which they have to traverse, the ocular spectra are found to be 
