JuNE 12, 1902] 
in raising those amounts in London, either by the generosity of 
its rich men or by grants from public funds, if only those in- 
terested in the making of a University would combine their 
efforts towards a common end. The task was rendered easier 
by the fact that in the building of the University they could 
utilise for University purposes in London many of the buildings 
and endowments already existing, and it was in the hope of 
inaugurating a common movement in that direction that 
University College had declared itself ready to be incorporated 
in the University. 
SCIENTIFIC SERIALS. 
Transactions of the American Mathematical Soctety, vol. iii. 
No 2, April.—E. W. Brown, on the small divisors in the lunar 
theory.—J. W. Young, on the holomorphisms of a group. This 
deals with non-abelian groups such that there is a one-one 
correspondence between the elements of the group and their ath 
powers.—F. R. Moulton, a simple non-desarguesian plane 
geometry. A simpler system than that given by Hilbert in his 
““ Grundlagen der Geometrie,” with a proof that his axioms 
I. 1-2, I1., I11., IV. 1-5, V. are fulfilled, while Desargues’ theorem 
is not true. —M. Bocher, on the real solutions of systems of two 
homogeneous linear differential equations of the first order. 
Propositions relating to y’=Py—(Qz, 2’=Ry-—Sz analogous’ to 
those given by Sturm for 7’ + Ay’ + gy=o0.—Charlotte A. Scott, 
ona recent method of dealing with the intersections of plane 
curves, The method in question is that of F. S. Macaulay (Proc. 
L.M.S. vols. xxxi., xxxii.).—E. V. Huntington, a complete set 
of postulates for the theory of absolute continuous magnitude. 
Six postulates are laid down, and shown to be consistent and 
independent of each other. A short paper by the same author 
follows, on the postulates for the theories of positive integral 
and positive rational numbers. 
Bulletin of the American Mathematical Soctety, second series, 
vol. viii. No. 8, May.—C. J. Keyser, concerning the angles and 
the angular determination of planes in 4-space.—D. R. Curtiss, 
note on the sufficient conditions for an analytic function.— 
Reviews :—Scheffer’s ‘‘ Theory of Surfaces,” by J. M. Page; 
**Some Recent Books on Mechanics,” by E. B. Wilson; ‘‘ The 
Galois Theory in Burnside and Panton’s Theory of Equations ” ; 
and shorter notices. 
SOCIETIES AND ACADEMIES. 
LONDON. 
Royal Society, March 20.—‘‘ Ona Peculiarity of the Cere- 
bral Commissures in certain Marsupialia, not hitherto recog- 
nised as a Distinctive Feature of the Diprotodontia,” by Prof. 
G. Elliot Smith, M.D., Ch.M. Communicated by Prof. G. B. 
Howes, F.R.S. 
It has been known for a considerable time that some of the 
fibres of the ventral commissure of the cerebrum in certain 
marsupials, instead of passing bodily into the ex¢erza/ capsule, 
form an aberrant bundle, which associates itself with the z7z/er7zal 
capsule so as to reach the dorsal area ‘of the neopallium by a 
shorter and slightly less circuitous course. 
This peculiarity has been recorded by the late W. H. 
Flower, by Johnson Symington and by Theodor Ziehen in 
Macropus, Phascolomys, Aepyprymnus, Phascolarctus and 
the Derbian Wallaby, and in Phalangista by myself. 
In 1894 I showed that while in the monotreme and Perameles 
the common mammalian relationship of the ventral commissure 
to the external capsule was found to obtain, in Trichosurus and 
Macropus some fibres of the ventral commissure were found to 
pursue the aberrant course indicated above. It was perhaps 
not unnatural to suppose that the increased size of the neo- 
pallium in these two genera was wholly responsible for the pre- 
sence of this aberrant bundle ; for it seemed that since the com- 
missural fibres of the neopallium had become too abundant to 
be wholly accommodated by the path provided by the external 
capsule, they, so to speak, had overflowed into the internal 
capsular route. 
Upon examining later a much larger series of marsupials, I 
soon became convinced that the explanation of the causation of 
this peculiarity which I then suggested could not be regarded as 
alone sufficient. I found the aberrant bundle in all members of 
the genera Macropus, Halmaturus, Hypsiprymnus, Dendro- 
NO. 1702, VOL. 66] 
NATURE 
165 
lagus, Trichosurus, Petaurus, Phascolarctus and Phascolomys, 
quite irrespective of the size of the brain and extent of the 
neopallium ; but I sought it in vain in Perameles, Sarcophilus, 
Dasyurus, Sminthopsis, Didelphys, Myrmecobius, and Noto- 
ryctes, even though many of these genera possess larger brains 
than some Diprotodonts.  _ 
These facts seemed to suggest that the aberrant bundle was a 
distinctive feature of the Diprotodont marsupials, and _ it 
appeared that the crucial test of this hypothesis would be 
afforded by the brain of Thylacinus, which, although that of a 
Polyprotodont, is almost, if not quite, as large as the brain of 
the largest Macropod. I accordingly submitted the cerebrum 
of Thylacinus to the test, and found no trace of the aberrant 
bundle, wherefore it is clear that the presence of this aberrant 
fasciculus of the ventral commissure is distinctive of the Dipro- 
odontia. 
The most pronounced growth tendency in the earliest 
mammals must have been an enormous increase in extent of the 
neopallium, for while at the beginning of the Eocene period 
this was almost as insignificant as it is in the Reptilia, in most 
recent mammals it attains a bulk which far exceeds that of the 
whole of the rest of the nervous system. This sudden expanse 
of the neopallium would lead to the development of an 
enormous mass of fibres which must find some outlet from the 
pallium ; and there are only three possible routes for commis- 
sural fibres of the neopallium to the mesial plane. There is 
first the external capsule, which chiefly consists in all mammals 
of such fibres passing to the ventral commissure; we find the 
second route in the path mapped out by the internal capsule 
from the dorsolateral neopallial area to it; and the third route 
can only involve the invasion of the alveus of the hippocampus. 
Adi the neopallial commissural fibres in the Polyprotodontia 
and some only of these in the Diprotodontia and Eutheria follow 
the first route. The commissural fibres, which spring from the 
dorso-lateral region of the neopallium in the Diprotodontia, 
crowded out of the first route pursue the second. In the 
Eutheria the neopallial commissural fibres from the dorso- lateral: 
region of the hemisphere forsake both the first and second 
routes and invade the alveus, so as tc form a new dorsally 
situated neopallial commissure, which is the corpus callosum. 
This hypothesis of the origin of the corpus callosum I have 
previously stated and discussed ; and I refer to the matter now 
merely to point out that the same determining cause which in 
the Eutheria calls the ‘‘ corpus callosum” into being is probably 
functional in bringing into existence the “‘aberrant bundle” in. 
the Diprotodontia. 
The development of any such commissural mass as the 
corpus callosum of the more highly organised Mammalia in the 
position occupied by its homologous fibres in the monotremes 
and marsupials would cause the most profound disruptions of 
the corpus striatum, optic thalamus, and the basal region of the 
brain, and the complete disorganisation of its whole ; and hence 
the new course taken by its fibres in the Eutheria. 
May 15.—‘‘ Cyanogenesis in Plants. Part II.—The Great 
Millet, Sorghum vulgare,’ by Wyndham R. Dunstan, M.A., 
F.R.S., Director of the Scientific Department of the Imperial 
Institute, and T, A. Henry, D.Sc. Lond. 
May 29.—‘‘ On the Structure of the Gills of the Lamelli- 
branchia,” by Dr. W. G. Ridewood. Communicated by 
E. Ray Lankester, M.A., F.R.S. 
This paper records the results of an investigation undertaken 
at the instance of Prof. E. Ray Lankester, F.R.S., and carried 
on under his supervision. 215 species of Lamellibranchia, 
belonging to 118 genera, were examined. The results demon- 
strate that although the minute structure of the gill, like the 
grosser Structure, cannot be taken as a criterion of genetic 
affinity, three main types of structure can be recognised, 
representing apparently three grades of complexity. 
The first type is distinguished by the mutual freedom of the 
gill leaflets into which the embryonic gill papillae expand. In 
the other two types the embryonic papillze elongate into fila- 
ments, which are held in juxtaposition by interlocking cilia, or 
by horizontal bars of cellular tissue. 
Evidence is produced to show that Pelseneer’s order Pseudo- 
lamellibranchia is based largely on a misconception of the 
relative value of the flatness or plication of the gill lamellz, and 
the presence or absence of principal filaments. 
In the family Solenidz particularly it is shown that different 
species and subgenera of the same genus may have their gill 
