304 
ANNALS NEW YORK ACADEMY OF SCIENCES 
was expressed as to the relationships of the genus Megalohyrax to the 
Hyracoidea and Mceritherium to the Proboscidia. The speaker stated that 
the collection of 1907 is being increased through the efforts of a representa¬ 
tive maintained in the Fayum. 
By charts and slides the geology of the region was illustrated, also the 
important topographic features and the methods employed in prospecting 
and collecting the fossils. 
Professor Crampton presented some of the general results obtained 
during investigations in 1906, 1907 and 1908, dealing with the variations and 
distribution of terrestrial snails of the genus Partula, inhabiting the Society 
Islands. The geographical and physiographical conditions were described. 
The islands of this group are volcanic peaks of a partly submerged range; 
these peaks occur sometimes in contact as in the double island of Tahiti, 
while others have greater or less distances between them. It is, therefore, 
possible to correlate the specific differences between the snails of different 
cones with the geographical proximity of the cones. As each island peak is 
furrowed more or less regularly by valleys, and as the snails occur only in 
the moist bottomlands of these valleys, it is possible to correlate the degree 
of resemblance between the species of neighboring valleys with the degree 
of geographical isolation. In brief, such correlations are extraordinarily 
close, as in the case of the classic Achatinellidse of the Hawaiian Islands 
described by Gulick. 
The varieties of snails occurring in different valleys of one and the same 
island, or in different islands of the group, cannot be regarded as produced 
by different environmental circumstances. Several illustrations were 
given which established this conclusion. The phenomena of mutation were 
observed in several islands. Finally the role of natural selection was deter¬ 
mined to be a much restricted one in the case of these snails. 
The Section then adjourned. 
L. Hussakof, 
Secretary. 
SECTION OF ASTRONOMY PHYSICS AND CHEMISTRY. 
April 20, 1909. 
By permission of Council no meeting was held. 
William Campbell, 
Secretary. 
