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DECEMBER 21, 1916] 
NATURE 
375 
fined to the restoration of a typical belemnite animal 
and its shell, as shown particularly by examples in the 
British Museum collection. Mr. Crick first demon- 
strated, by means of a rough model, the construction 
of the belemnite shell, including the guard or rostrum, 
the phragmocone with its ventrally situated siphuncle, 
and its thin envelope, the conotheca, with its forward 
prolongation and expansion (on the dorsal side) 
known as the pro-ostracum. He then exhibited photo- 
graphic slides of examples in the British Museum col- 
lection showing these various characters, and noted 
the abrupt termination of the chambered cone on the 
lower part of the pro-ostracum, of which the dorsal 
surface may have been partly or almost completely 
covered by a thin forward extension of the guard. 
Mathematical Society, December 14.—Prof. H. M. 
Macdonald, president, in the chair.—Prof. W. Burn- 
side: The efficiency of a surface of discontinuity re- 
garded as a propeller.—G. H. Hardy and S. Rama- 
nujan; (1) Proof that almost all numbers N are com- 
posed of about loglogN prime factors. (2) An 
asymptotic formula for the number of partitions of a 
number.—G. N. Watson : The harmonic functions asso- 
ciated with the parabolic cylinder (second paper).— 
Prof. D. Buchanan; Orbits asymptotic to an isosceles- 
triangle solution of the problem of three bodies.—Prof. 
H. S. Carslaw: Diffraction of waves by a wedge of 
any angle.—Prof. L. J. Rogers : Two theorems of com- 
binatory analysis and two allied identities.—Prof. 
W. H. Young and Mrs. Young: (1) The internal struc- 
ture of a set of points in space of any number of 
dimensions. (2) The inherently crystalline structure 
of a function of any number of variables. 
EDINBURGH. 
Royal Society, November 6.—Dr. J. Horne, presi- 
dent, in the chair.—The President opened the 
session with a short address on the relations of in- 
dustry and science.—Dr. J. Tait: Experiments and 
observations on Crustacea. Part i. Immersion ex- 
periments on Ligia oceanica. In distilled, or in tap, 
water Ligia dies within two days. When sea-water 
is added the period of survival is increased, and in 
full sea-water, steadily aerated, Ligia can live without 
food for three months. Size and condition as regards 
moult influence the period of survival. Part ii. The 
moulting of. Isopods. Isopods appear.to moult in 
two stages. Splitting occurs (1) transversely between 
the fourth and fifth free thoracic segments; (2) longi- 
tudinally at junction of coxopodite with tergite, thus 
revealing otherwise invisible lines of concurrence of 
segments. Ligiz kept for weeks without food in sea- 
water moult normally. The opinion expressed by 
Réaumur that a crustacean moults because it has 
grown too large for its coat is incorrect. } 
November 20.—Dr. J. Horne, president, in the chair. 
—Prof, E. T. Whittaker: The adelphic integral in 
dynamics. The adelphic integral is defined to be such 
that the infinitesimal transformation corresponding to 
it transforms the members of a family of periodic 
orbits (corresponding to the same value of the con- 
stant of energy) into each other. It is shown that a 
dynamical problem with two degrees of freedom 
possesses only one really distinct adelphic integral, and 
that the finding of this integral is the most natural 
way of obtaining the complete solution of the problem. 
The integral is obtained as an infinite series, and it 
is shown that the difficulties connected with Poincaré’s 
theorem on the non-convergence of the series of celes- 
tial mechanics may be surmounted by its means.—- 
Dr. J. Tait: Experiments and observations on Crus- 
tacea. Part iii. Limb flexures and limb taxis in the 
Pericarida. The design and arrangement of the limbs 
NO. 2460, VOL. 98] 
in five orders were described, the mode of inquiry 
being physiological, advantage being also taken of the 
principle of analogy. A series of swimming limbs 
(Mysidacea) develop tri-alternate flexures when the 
animal passes from a homogeneous fluid medium to 
a fixed bounding surface. The proximal segments of 
these limbs are at first directed laterally outwards from 
the body (Cumacea, Tanaidacea), and the limbs from 
two groups, anterior and posterior. By a process 
akin to the rotation that occurs in vertebrate limbs 
the principal plane of flexure comes to lie antero- 
posteriorly in the Cammaridea. In the Isopoda fur- 
ther rotation has occurred, producing a taxis suitable 
for clinging. In the isopodan limb the most proximal 
joint is a universal hinge like a spheroidal bony joint. 
The author discussed the application of functional con- 
ceptions to the study of structure. 
DvBLIN. 
Royal Irish Academy, November 30.—The Most Rev. 
J. H. Bernard, Archbishop of Dublin, president, in the 
chair.—H. Ryan and W. M. O’Riordan: The tinctorial 
constituents of some lichens which are used as dyes 
in Ireland. Four species of lichens, viz. Parmelia 
saxatilis, Ach., Ramalina scopulorum, Ach., Ramalina 
cuspidata, Nyl., and Physcia parietina, De Not, were 
examined. The first three of these are known to have 
been largely used in the west of Ireland, and also in 
parts of Scotland, for dyeing wool a brownish colour. 
The chief constituents of these three lichens were found 
to be as follows :—Parmelia saxatilis, Ach., contains 
stereocaulic acid and. salazinic acid, C;,H.,O,,; R. 
scopulorum, Ach., contains scopuloric acid, Cnt. . Of, 
and d-usnic acid; R. cuspidata, Nyl., contains cuspi- 
datic acid, C,,H,,0.., or C,,H,,O,,, and d-usnic acid. 
The tinctorial properties of the lichens were found to 
be due to the presence in them of. salazinic acid, scopu- 
loric acid, and cuspidatic acid respectively. The fourth 
lichen, Physcia parietina, De Not, is not largely used 
as a dye. It contains, however, a yellow substance, 
physcione, which, when demethylated by means of 
strong sulphuric acid, yields emodin, which dyes wool 
an orange colour.—H. Ryan and P. Ryan: The con- 
densation of aldehydes with ketones. III.—Benzalde- 
hyde with methyl isopropyl ketone. Benzaldehyde 
condenses with methyl isopropyl ketone to form the 
benzylidene derivative of diphenyldimethyltetrahydro- 
pyrone, which was previously obtained from benz- 
aldehyde and dimethylacetylacetone. | Monomethyl- 
acetylacetone with benzaldehyde forms another com- 
pound melting at 157° C. Benzaldehyde also condenses 
with ethylacetoacetic ester to yield cinnamoylbutyric 
acid.—J. Algar: Unsaturated ketones derived from 
diaceto-orcinol. In this .communication is described 
the preparation of diaceto-orcinol from orcinol- 
diacetate. It is identical with the diaceto-orcinol ob- 
tained by Collie from diacetylacetone. Diaceto-orcinol 
condenses with aldehydes in the presence of alcoholic 
caustic soda, and in this manner unsaturated ketones 
were prepared. A description is given of the prepara- 
tion of dibenzylidene-, dianisylidene-, diveratrylidene-, 
and dipiperonylidene-diaceto-orcinol. 
Paris. 
. Academy of Sciences, November 27.—M. Camille Jor- 
dan in the chair.—E. Picard: The integrals of total 
differentials relating to regular algebraical surfaces.— 
G. Bigourdan: The position and co-ordinates of the 
astronomical station of the island of Notre-Dame. 
The works of Auzout. This station was where Auzout 
made a part of his observations, constructed his tele- 
scopes, the largest up to, that time, and invented the 
micrometer with movable thread.—C, Guichard ; The 
K networks of a quadric of revolution. — F. 
Gonnessiat: A star with a large proper motion. 
