January 28, 1897] 
NATURE 
311 
sharply defined, and its relation to the external outline well 
shown. These sciagraphs, as well as those of a series of mollusca 
also exhibited, were taken with a Crookes’ tube of the ordinary 
focus pattern actuated by a powerful induction-coil giving $-inch 
sparks, and the prints in every case were made from untouched 
negatives. Prof. Howes offered some remarks on the series of 
batrachians and reptiles, and Mr. B. B. Woodward commented 
upon the details of structure which were made apparent in the 
sciagraphs of mollusca.—Mr. J. E. Harting exhibited a supposed 
hybrid between the common brown hare (Zepus témédus) and 
the Irish hare (Lepzs varzabilis) recently obtained in Carnarvon- 
shire, where the latter species had been introduced in 1878. He 
compared the specimen in question with examples of both the 
above-named species, and contrasted their distinguishing pecu- 
liarities, pointing out the intermediate characters exhibited by 
the supposed hybrid. His remarks were criticised by the 
President, who thought that too much stress should not be laid 
upon external appearance and colour; that the question of 
hybridity should rather be determined by comparing the 
relative measurements of the leg-bones; and that the Irish 
hare should be compared in detail with the hare of Southern 
Europe (Z. mertdionalis or mediterraneus). Prof. Howes drew 
attention to Nathusius’s observations upon the Peyer’s patches 
of the leporines, and pointed to the necessity for examination 
of the viscera. Mr. Barrett Hamilton, who was present as a 
visitor, was inclined to regard the supposed hybrid asan example 
of the ordinary brown hare turhing white in winter, hitherto 
unnoticed in this country. Mr. Thomas Christy inquired what 
position the so-called Belgian hare or leporine occupied in 
relation to the question of hybridity ; and was answered that the 
popular notion of that animal being a hybrid between hare and 
rabbit was fallacious, since it was nothing more than an over- 
grown tame rabbit coloured like a hare.—Mr. B. B. Woodward 
gave a demonstration, illustrated with lantern-slides, of M. F. 
Bernard’s researches into the development of the hinge of 
bivalve shells.—On behalf of Dr. A. J. Ewart, a paper was read 
in continuation of one previously communicated by him and 
entitled ‘‘ Further Observations on Assimilatory Inhibition.” — 
Mr. W. C. Worsdell gave the chief facts of a paper dealing with 
the development of the ovule of CAréstzsonza, a genus of the 
Orobanchez. Referring to Prof. Koch’s detailed account of the 
development of the ovule of Ovobanche he remarked that 
Christzsonia as a parasitic plant was of such interest and differed 
so much in its vegetative structure from Ovobanche, that it 
seemed to be worth while to record the facts of its embryological 
development. A brief description of the vegetative parts of the 
plant was then given. 
ment of the embryo-sac and the embryo. This was shown to 
follow essentially the same lines as in Orodanche. Finally, it 
was pointed out that in a great many plants the vegetative and 
the reproductive organs have not always, by any means, a 
parallel development. A striking instance of this was to be seen 
in Christésonta. The paper was criticised by Dr. D. IH. Scott, 
who testified to the importance and interest of some of the facts 
established —On behalf of Dr. L. O. Howard, entomologist to 
the U.S. Department of Agriculture, a paper was read on the 
Chalcididze of the Island of Grenada, West Indies. This paper, 
communicated by Mr. F. D. Godman, F.R.S , dealt with the 
Chalcididze collected by Mr. H. H. Smith, under the auspices of 
the British Association Committee for investigating the fauna 
and flora of the West Indian Islands. The collection consisted of 
from 600 to 700 specimens, and comprised six new genera and 
seventy-two new species, which were described. The geo- 
graphical relationships of the group were discussed. 
Geological Society, January 6.—Dr. Henry Hicks, F.R.S., 
President, in the chair.—On the structure of the skull of a 
Pliosaur, by C. W. Andrews. The paper deals with a specimen 
of the Plesiosaurian known as Péosauryus ferox, Sauvage, ob- 
tained by Mr. A. N. Leeds from the Oxford clay near Peter- 
borough, and now in the British Museum, and perhaps the 
finest Pliosaur skull known. The author gavea detailed descrip- 
tion of the skull which formed the subject of the paper.—On 
the Pembroke earthquakes of August 1892, and November 
1893, by Dr. Charles Davison. In the part of the paper referring 
to the origin of these earthquakes and their connection with 
faults, the author pointed out the possible value of the study of 
earthquakes in supplementing geological surveys. For more 
than fifty years prior to the earthquakes of 1892-93, there appear 
to have been no slips of importance along the fault-system of 
the area. After this prolonged interval of repose, the earlier 
NO. 1422, VOL. 55 | 
The author also described the develop- | 
movements took place’ along transverse (north and _ south) 
faults, and the later along longitudinal (east and west) ones. 
The three faults of the latter series, which the author connected 
with the disturbances, lie successively one to the north of the 
other, as if the abrupt displacement of a rock-mass over one 
thrust-plane impelled the advance of those immediately below. 
There can be little doubt that the fault-slips of 1892 affected the 
conditions of stress along the neighbouring transverse fault, so 
that the displacements along it occurred earlier than they might 
otherwise have done. In the discussion that followed the read- 
ing of the paper, the President said that the author’s inquiries 
into the relationship between earthquakes and faults were of 
great interest. It was well known that the older rocks in Pem- 
brokeshire have been much crushed and broken, and that thrust- 
faults of great magnitude occurred there. The Rev. J. F. Blake 
remarked upon the apparent absence of any signs of disturbance 
on the surface. If these earthquakes were due to slips, it was 
strange that none of them should yield this evidence. In the 
cases previously described by the author the principal evidence 
was the association with well-known faults, which might be lines 
of fresh dislocation ; but in the present instance faults had to 
be hypothecated. Though, therefore, the speaker believed the 
theory to be the true one, the evidence for it appeared extremely 
weak.—Changes of level in the Bermuda Islands, by Prof. Ralph 
S. Tarr. The author gave a summary of previous writings bear- 
ing upon the geology of the Bermudas; but his own researches 
point to a rather more complicated series of changes than those: 
which have been inferred by other writers. The formation of 
the ‘“‘base-rock” or ‘* beach-rock” occurred at some period 
which cannot be accurately ascertained at present, owing to the 
fragmentary nature of the included fossils. It may have been 
formed in Pleistocene or even late Tertiary times. After its 
formation it was converted into a dense limestone and then 
eroded, probably by subaerial agents, and finally attacked by 
the waves at an elevation of at least fifteen feet above present 
sea-level ; during this stage it was covered by beach-deposits of 
pebbles and shells, which were accumulated in a period so 
recent that the contained fossils are of the same species as the 
organisms living in the neighbouring sea. Then followed an 
uplift, during which land-shells lived on the beach-deposits ; but 
these were soon covered by blown sand —the principal accumula- 
tions of the islands, and the outline of the islands was perfected 
by the action of the winds. This was done at an elevation 
which was at one time certainly as much as 40 or 50 feet above 
present sea-level. The author adduced evidence of a depression 
since this accumulation, causing land to disappear and the out- 
line of the area to become very irregular; and he proves that 
these changes cannot be accounted for solely by erosion, as some 
have maintained. There are indications that the land is at 
present quiescent. It appears, then, that most of the work of 
construction of the Bermudas has been done in recent times 
(see NATURE, vol. liv. p. 101.) 
Paris. 
Academy of Sciences, January 18.—M. A. Chatin in the 
chair.— Researches on helium, by M. Berthelot. Helium, in 
contact with mercury and benzene, is slowly absorbed during 
the prolonged action of the silent discharge. After the sparking 
has proceeded for some time, a fine orange glow appears, 
sufficiently bright to be visible in daylight, which examined with 
the spectroscope under ordinary atmospheric pressure shows the 
characteristic lines of helium and mercury, together with some 
hydrocarbon bands. At a red heat the resinous compound 
breaks up, reforming helium.—Remarks on the specific heats of 
the elementary gases, and on their atomic constitution, by M. 
Berthelot. In a vésamdé of the results obtained for the specific 
heats of the elementary gases, it is shown that these fall into. 
four groups, comprising the monatomic gases, helium, argon, and 
mercury, diatomic gases other than the halogens, the halogens, 
and tetratomic gases such as phosphorus and arsenic.—Methods 
for comparing, with the aid of the electric spark, the times of 
oscillations of two regulated pendulums of nearly equal period, 
by M. G. Lippmann. The two pendulums are twice photo- 
graphed by the sparks from a jar discharge at a known interval 
of time, and the exact phase of oscillation of each pendulum 
measured micrometrically upon the negative. The accuracy of 
the method is much higher than the method of coincidences. -—- 
Classification of the chemical elements, by M. Lecoq de 
Boisbaudran.—M, Potain presented a series of radiographs on 
behalf of M. Serbanesco, of subjects affected by gout or chronic 
