Marcu 22, 1912] 
yet have derived its oil from them in the past. 
The oil has been largely moved away as 
formed. Hence, richly petroliferous shales 
are not a necessary indication in oil pros- 
pecting. 
(d) Gravitational sorting requires not only 
a certain necessary degree of dip, but also a 
necessary degree of porosity, because in inter- 
stices below a certain size, surface tension 
checks the motion necessary for gravitational 
sorting. For this reason, water-filled shales 
or very fine-grained sandstones or limestones 
lying above porous rocks, act as impervious 
barriers, instead of allowing the oil and gas 
to reach the surface. 
(e) While gas can move in a water-satu- 
rated rock with a lower degree of dip or with 
a lower porosity than oil, yet, since the gas 
bubble carries with it a pellicle of oil, a cer- 
tain quantity of oil can be carried where it 
would not otherwise move. 
(f) Inasmuch as all porous reservoirs in the 
strata constituting our oil fields were orig- 
inally water-filled, dry porous sands really 
contain gas. It is not recognized because not 
under sufficient pressure to escape noticeably. 
This gas has been contributed to it generally 
by neighboring strata, and may have served 
for the transport of oil. As gas becomes more 
expensive, this gas may be extracted by suc- 
tion, as is already done in gas-sands which 
have lost their pressure. 
Of course, the principles here proposed are 
not exclusive of the action of gravitation and 
moving water, but act in conjunction there- 
with. 
Roswett H. Jonnson 
BARTLESVILLE, OKLAHOMA 
THE AMERICAN SOCIETY OF ZCOLOGISTS 
THE Eastern and Central Branches of the Amer- 
ican Society of Zoologists met in joint session at 
Princeton University, Princeton, N. J., December 
27 and 29, 1911, in conjunction with the American 
Society of Naturalists and the American Associa- 
tion of Anatomists. 
The following officers of the Eastern Branch for 
the ensuing year were elected: 
President—A. G. Mayer, Carnegie Institution of 
Washington, D. C. 
SCIENCE 
459 
Vice-president—G. A. Drew, Marine Biological 
Laboratory, Woods Hole, Mass. 
Secretary-treasurer—John HH. Gerould, Dart- 
mouth College, Hanover, N. H. 
Additional Member of the Executive Committee 
—H. E. Jordan, University of Virginia. 
These officers, in addition to David H. Tennent 
and Ross G. Harrison, will constitute the executive 
committee of the Eastern Branch. It is under- 
stood that the same officers of the Central Branch 
that served last year will continue in office. 
The following persons were elected members of 
the American Society of Zoologists: 
Central Branch—J. Frank Daniel, University of 
California; T. W. Galloway, James Milliken Uni- 
versity; Wilhelmine Enteman Key, Lombard Col- 
lege; George R. La Rue, University of Michigan; 
Joseph A. Long, University of California; Marian 
L. Shorey, Milwaukee-Downer College; Aaron F. 
Shull, University of Michigan; Leroy D. Swingle, 
Nebraska Wesleyan University. 
Eastern Branch—Thomas Barbour, Harvard 
University; M. T. Burrows, Cornell University 
Medical College; H. S. Colton, University of 
Pennsylvania; E. D. Congdon, Cornell University 
Medical College; Henry Fox, Ursinus College; 
Leland Griggs, Dartmouth College; Mary J. 
Hogue, Mt. Holyoke College; M. H. Jacobs, Uni- 
versity of Pennsylvania; H. G. Kribs, University 
of Pennsylvania; C. V. Morrill, New York Uni- 
versity and Bellevue Hospital Medical College; 
H. D. Reed, Cornell University; A. H. Wright, 
Cornell University. 
The following committee was appointed to 
consider during the ensuing year the problem of 
the organization of the society, and to prepare 
a new constitution: H. V. Wilson, chairman; HE. G. 
Conklin, G. A. Drew and R. G. Harrison (Eastern 
Branch); F. R. Lillie, W. A. Locy and M. M. 
Metcalf (Central Branch). 
The following papers were presented at the 
meeting, either in full or by title: 
The Sense of Smell in Necturus maculatus: R. E. 
SHELDON, University of Pittsburgh. 
Conjugation and its Significance in the Ciliate, 
Didinium: S. O. Mast, Johns Hopkins Univer- 
sity. 
Didinia about to conjugate decrease nearly 
three fourths in size, and the anterior ends become 
considerably flattened. They find each other by 
random movements, join anterior end to anterior 
end and remain together from four to twelve 
hours or longer, depending largely upon the tem- 
