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than point out that while the first part of the paper contained a 
resumé of what was known on the subject of hybridization and 
the fertility of hybrids, which would be most useful as a 
paper of reference, the second part was of a much more 
valuable character. It embraced the careful work of eight or 
nine years on hybridization in fishes, by perhaps the most 
skilled observer on the subject we have, and therefore would 
add much to the value of the Transactions. 
Mr Medland shewed some photographs of some sections 
of Caswell Bay, near Swansea, and explained the physical 
features of the district. 
Mr Buckman exhibited two Ammonites so exactly alike 
that it would naturally be thought that they were the same 
species; and yet he stated that not only was this not so, but 
that they belonged to two different genera. These conclusions 
were arrived at by a knowledge of the ancestry of each species, 
and by following the series of changes by which they had each 
been evolved from very different forms. These two species occur 
in the Cephalopoda beds—say the top of the Upper Lias; but 
the Lower Lias ancestor of one was a strongly-keeled species, 
while that of the other was a small uncarinated species. The 
first branch has remained almost stationary, so far as important 
changes go, and has only begun to lose its distinctive keel; the 
other branch has undergone several changes, each causing it to 
become more like the first, and at last it has completed this 
process by putting forth a small keel. Still there remain two 
slight differences which may be detected by close study, and 
which may be relied on to separate the members of the two 
converging genera : one is—a bend of the ribbing on the lateral 
area of the first, which is not seen on the second, and this is 
accompanied by a longer ventral projection ; the other is—that 
the inner part of the suture-line of the second hangs down 
obliquely, while that of the first is continued straight across. 
Such minute—but withal extremely important—characters as 
these were unobserved by the older authors, and consequently 
were not, necessarily, reproduced with exactitude by artists, 
upon their plates: hence great difficulty is experienced in 
