220 
which genus it appears most nearly related, 
by (1) the presence of a functional Pe ot 
good size. This tooth is absent in Aphelops; 
(2) by a much more brachyodont dentition; 
(8) by the presence of a heavy external and 
internal cingulum on all teeth of the grind- 
ing series, but the last molar, where it is re- 
duced. 
This brachyodont condition, as compared 
with Aphelops, corresponds to the difference 
in horizon, assuming them to be in the same 
approximate ancestral line. The typical 
Aphelops megalodum is from the Middle 
Miocene, the present genus and species from 
the Lower Miocene. 
Epiaphelops does not appear to be derivable 
from Cenopus, as in all known species of 
Cenopus the first lower premolar is absent, 
or a vestigial, variable, character. In this re- 
spect Hpiaphelops is more primitive than 
Cenopus, as P, is large and functional. 
Comparison with other Oligocene types does 
not appear profitable. 
Epiaphelops virgasectus is somewhat larger 
than Aphelops megalodum. As the other 
specimens in the collection of the writer re- 
ferable to this type are not surely associated, 
they are best unpublished for the present, but 
suffice it to say that when this form is better 
known, other characters are present which 
will more clearly characterize it. A more 
complete description will appear later. 
Harotp JAMES Cook 
AGATE, NEBRASKA, 
December 20, 1911 
THE AMERICAN ASSOCIATION FOR THE 
ADVANCEMENT OF SCIENCE 
SECTION A—MATHEMATICS AND 
ASTRONOMY 
As the Astronomical and Astrophysical Society 
of America held a regular meeting in affiliation 
with the American Association, and as the Amer- 
ican Mathematical Society held its annual meeting 
at the same time in New York City, the special 
program of Section A was confined to one session. 
This was a joint session with the Astronomical 
and Astrophysical Society, and the program con- 
sisted of the vice-presidential address by E. H. 
SCIENCE 
[N.S. Vou. XXXV. No. 898 
Moore, of the University of Chicago, and of two 
papers given, on special invitation, by J. A. Met- 
calf and Lewis Boss. 
An abstract of the paper by Lewis Boss, entitled 
“‘Recent Researches as to the Systematic Motions 
of the Stars,’’ is as follows: 
The proper motions of stars are so small, and 
are so difficult to measure with proportionate 
accuracy that the successful determination of sys- 
tematic peculiarities in the arrangements of the 
motions themselves must depend upon great sys- 
tematic accuracy in the measurements of those 
motions. Therefore, when the department of 
meridian astrometry was established at the Dudley 
Observatory about six years ago with the support 
of the Carnegie Institution of Washington its first 
work of investigation was to continue to comple- 
tion the work it had begun with the object of 
ascertaining the proper motions of the brighter 
stars which had been most observed with precision 
in the past, with all practicable completeness and 
accuracy, both in the casual and systematic sense, 
with the ultimate purpose of making this work the 
basis of studying the systematic peculiarities of 
these motions in order to throw further light on 
the mechanism of the visible universe. 
About two years ago the Carnegie Institution of 
Washington published the result of this research 
in a volume entitled ‘‘Preliminary Catalogue of 
6,188 Stars.’’ For each star the position was 
given for 1900 together with the proper motion, 
etc., necessary for reducing those positions to any 
other epoch. This material was first employed for 
deriving new values of the precession as well as 
the direction of solar motion. The latter was 
found to be, for 1875: R.A. 270°.7, Decl. + 34°.3 
(A.J. 614). The stars employed in this discussion 
cover the entire sky from the north to the south 
pole; so that the direction of the solar motion 
came out with very great weight and at the same 
time independently of the precession. 
Next were deduced the facts in regard to an 
interesting moving cluster of stars in the constel- 
lation, Taurus. Each of the 41 stars appears to 
be moving toward a point in the sky in R.A. 6" 7™, 
Decl. + 7°. The velocities of motion of the sev- 
eral stars are approximately the same. Very 
recently Mr. Benjamin Boss, of the department 
of meridian astrometry, identified a group of 11 
or 12 large proper motions scattered widely over 
the sky between declinations + 42° and — 81°, 
which converge nearly in a point at R.A. 6"37™, 
Decl. + 0°.5. The velocities of these stars toward 
the point cited seem to be uniformly about 95 
