166 
REPOETS OF MEETINGS. 
series of cells or chambers, the total number of which is a 
multiple of six. It is a remarkable circumstance that among 
the corals which exist in the Palseozoic formations we find none 
with six divisions, four being the number. It is within the 
septa that the coral is deposited, the animal growing upwards 
as the formation proceeds. Reproduction takes place by budding, 
an instance of which Mr. Leipner described as having occurred 
under his eye in the case of a coral in an aquarium. Budding 
may take place in a four-fold manner — from the base, side, 
margin, or from the disc itself. The area in which reef-huilding 
corals occur is limited. They require for full development a 
temperature ranging between 70 and 85 degrees Fahr., and the 
extreme depth must not exceed 20 fathoms. The distribution 
is not uniform, but it is in the Central Pacific Ocean that we 
find reefs of the greatest extent ; while in the Atlantic and 
other quarters of the globe they vary considerably in size, 
according to the nature of their surroundings ; the formation of 
coral being checked by the cold Antarctic currents, fresh water, 
and the debris brought down by rivers. Branch coral grows 
more rapidly than the massive variet}^ In the case of a sunken 
vessel, over which the deposit had gradually formed, it was found 
to increase at the rate of 3 in. per year. Want of time prevented 
Mr. Leipner from entering upon several other points connected 
with the subject, and at the close a unanimous vote of thanks 
was accorded him for his very interesting and instructive 
communication. 
On October 7th, the Society met, when Mr. Leipner gave, as 
the result of his holiday tour, “ A Naturalist's Ramble in 
Guernsey,” which appears in full in this part of the Proceedings. 
On November 4th, Professor Thompson exhibited his new 
Phonautograph, \A hich is fully described by him in the preceding 
pages. He was followed by Professor Sollas on “ Siliceous 
Skeletons, and their Mineral I’ransformations.” He commenced 
