10 
was shown to possess, in addition to its peculiar shape, a wealth 
of prismatic colouring of great delicacy. Shells consisting of 
eight pieces were given as examples of a family which live like 
limpets attached to rocks on the English coasts, some being found 
at Bulverhythe. They rejoiced in the name of sea-woodlice, and, 
like those creatures, could roll themselves into a ball. The shells 
of the rock borers were white, adorned with prickly sculpture, 
and although thin, were strong. The valves of all the species 
did not meet, and when such was the case the spaces were filled 
in with other portions termed accessory plates. The animals 
forming these shells emitted a phosphorescent light. This was 
shown in some living specimens which the lecturer had procured 
from the rocks for the occasion. The opening and closing of 
oyster valves was also demonstrated with specimens. In acon- 
cluding view a cluster of beautiful barnacles was shown. These, 
it was stated, did not belong to shells proper, because the 
structure of the barnacle was widely different from that of a 
mollusc, nevertheless most people spoke of them as shell fish. 
The illustration was from a photograph taken by the lecturer’s 
father some years ago when a log of wood about 3oft. long was 
washed ashore at St. Leonards, and was almost covered with 
living barnacles. 
WEDNESDAY, JANUARY 20TH, 1904. 
Memory and Its Diseases. 
BY 
Ma. A. M: JSYDNEV-FURNER, 
M.R.CS., F.Z.S. 
OMMENCING with aclassification of the degrees of memory, 
the Lecturer enumerated four. First there was the conscious 
but unorganised degree, which was evanescent, and was illustrated 
in the greater number of incidents which pass under our daily 
observation, and which in many cases disappear for ever from the 
. memory. Next came the conscious and semi-organised degree, 
shown in the grasping of a language or manual art which is being 
learnt, but in which the student is not proficient. The third 
degree was less conscious and nearly organised, the memory of 
the mother tongue being the case in point here. The fourth was 
