210 
secretary's report, 1906. 
of the structures, which would become more speciahsed. This 
was what was known as ana-genesis. But a speciaHsation 
which suited an animal for a particular environment would 
unsuit it for any changed conditions. Hence the worker would 
find that under changed conditions the gens showed an attempt 
to return to the former structural arrangement, which was 
more plastic. That return was called kata-genesis. As a rule 
it was unable to return to a form which was ready for further 
modifications, and under these circumstances the animal seemed 
to use the remaining energy of the race in the way of ornamenta- 
tion ol its exo-skeleton. Thus, one found shells putting on spines 
and vesicles which were of no particular use, but merely for 
ornament. Once that process began the extinction of the race 
was in sight. Then in the passage from one gens to another 
the worker might find one species possessing the characteristics 
of another species. The assimilation of two distinct genera took 
place very slowly until their convergency, when changes took 
place exceedingly rapidly, and new species were almost imme- 
diately produced. That was called saltation. Dr. Vaughan 
went on to compare the working of these laws with the ordinary 
laws of evolution — the law of natural selection and of the elimina- 
tion of the unfit, and the struggle for existence, and to compare 
them also with Lamarck's theory of the transmission of acquired 
characteristics and with Weismann's theory. 
Thanks were formally expressed to Dr. Vaughan and to 
the Chairman for their share in the proceedings, and expression 
was given to the feeling of gratitude that the ideas and work 
into which they had initiated the members had added greatly 
to the interest of the excursions, and provided abundant em- 
ployment for the future. 
A vote of thanks was also passed to the Chairman and 
Engineer of the Bradford Corporation Waterworks Committee 
for their kind permission to freely examine the Angram sections. 
On the following Tuesday the party separated into two 
sections, one under Dr. Hind's leadership visiting the shell beds 
in the Millstone Grit at Hampsthwaite and Cay ton Gill. The 
others made an excursion up Merryfield and Brandstone Becks 
and Burn Gill in search of glacial evidence. Much satisfaction 
