JUNE 22, 1899] 
Bed was shown to be, probably, not identical with C. carnu- 
torum, Laug., but a synonym of C. delerandi, Lart.—Dr. A. 
Giinther, F.R.S., gave an account of a collection of freshwater 
fishes made by Mr. R. B. N. Walker in the rivers of the Gold 
Coast. The collection, though a small one, was of consider- 
able interest, as it contained specimens of several forms pre- 
viously unknown from the Gold Coast. It had led the author 
to prepare a critical revision of the Gaboon species of Chrys- 
tchthys, which were numerous and difficult of discrimination. 
Eight new species were described in this paper, viz. Petersits 
occidentalis and seven species of Chrysichthys. —A communi- 
cation was read from Dr. R. O. Cunningham, containing notes 
on the structure of Laborde’s shark (Zuprotomicrus labordit), 
an example of which had recently been presented to the museum 
of Queen’s College, Belfast.—A communication was read from 
Mr. J. Stanley Gardiner, containing an account of the Astrzeid 
corals which he had collected in the South Pacific. The col- 
lection contained specimens of twelve genera and forty-eight 
species, six of the latter being new to science. —A communi- 
cation was read from Dr. W. T. Blanford, F.R.S., containing 
the characters of several species of shells of the genera S¢rep- 
vaxis and E£nnea from India, Ceylon and Burma. Of the 
former genus three species were described as new, bringing 
up the number of species of this genus, described from Southern 
India, to eleven. Of the genus Eynea two new species were 
described. 
Mathematical Society, June 8.—Lord Kelvin, G.C.V.O., 
President, in the chair.—The President announced that the 
‘Council had awarded the De Morgan medal to Prof. W. Burn- 
side, F.R.S., for his researches in mathematics, particularly 
in the theory of groups of finite order. Prof. Burnside, who was 
present, briefly returned thanks for the award, which had taken 
him by surprise.—Prof. Mittag Leffler, of Stockholm, a foreign 
member, was admitted into the Society, and made an interesting 
communication (in French) on the convergency of series. Prof. 
Elliott, F.R.S., Prof. Love, F.R.S., and Dr. Hobson, F.R.S., 
offered some remarks, to which Prof. Mittag Leffler replied.— 
The President spoke on ‘‘ Solitary waves, equivoluminal and 
irrotational, in an elastic solid.” In the course of his address he 
showed how greatly mathematicians were indebted to Sir George 
Stokes, F.R.S. Prof. Love said he had been much interested 
in the diagrams shown by Lord Kelvin. He afterwards gave a 
sketch of a paper by Prof. J. H. Michell on the transmission of 
stress across a plane of discontinuity in an isotropic elastic solid, 
and the potential solutions for a plane boundary.—The follow- 
ing papers were taken as read: On several classes of simple 
groups, Dr. G. A. Miller ; on theta differential equations and 
expansions, Rev. M. M. U. Wilkinson; finite current sheets, 
Mr. J. H. Jeans ; (1) on a congruence theorem having reference 
to an extensive class of coefficients ; (2) on a set of coefficients 
analogous to the Eulerian numbers, Dr. Glaisher, F.R.S. ; (1) 
the reduction of a linear substitution ta its canonical form ; (2) 
on the integration of systems of total differential equations, 
Prof. A. C. Dixon. 
Entomological Society, June 7.—Mr. G. Verrall, Presi- 
dent, in the chair.—Mr. J. J. Walker exhibited on behalf of 
Mr. G. F. Mathew a number of interesting Lepidoptera, 
chiefly from the Mediterranean region, and including amongst 
others the following: examples of Zhazs polyxena, Schiff., 
var. ochyacea, Staud., having an unusually deep and rich 
colour, bred from larve found at Platza, Greece; male and 
female of Zhestor ballus, Hb., from Alexandria, the male re- 
markable in being largely marked with orange on the upper side 
of the front wings; and a singular aberration, from Corfu, of 
Melitaca didyma, Ochs., with central band of black spots very 
strongly marked on both wings, the other spots being obsolete 
and the ground colour pale fulvous.—Mr. E. E. Green exhibited 
a teratomorphic specimen of a zygenid moth, Chalcosta venosa, 
Walk., which he had found at rest on a leaf in Ceylon. In this 
specimen four wings were present on the left side, the hindmost 
being almost as fully developed as the normal hind wing on the 
right side, while the other three appeared to be attached to the 
meso-thorax, He also showed larvze and pupe of insects in 
air-tight glass tubes in which a little cotton wool, sprinkled with 
formalin, had been placed. The specimens, which had been 
thus. preserved for nearly two years, had lost little of their 
original colour or brilliancy.—Mr. Gahan exhibited pupa-cases 
of a Longicorn beetle, Plocederus obesus, Gah., which were re- 
markable in being composed almost wholly of carbonate of lime. 
NO. 1547, VOL. 60] 
NATURE 
191 
It was not known how the pupa-cases were fabricated, but pre- 
sumably the larvze must possess special lime-secreting glands. — 
Mr. R. McLachlan read a paper on a second Asiatic species 
of Corydalis, and exhibited the male ,type of the species 
described, which he proposed to name Corydalis orientalis. 
He said the first Asiatic species of Corydalis was described and 
figured by Prof. Wood-Mason in 1884, the genus up to that time 
having been considered to be peculiarly American. Mr. H 
Elwes communicated a paper on the Lepidoptera of the Altai 
Mountains, and the Rev. A. E. Eaton a paper entitled ‘‘ An 
annotated list of the Zphemertdae of New Zealand.” 
Geological Society, June 7.—W. Whitaker, F.R.S., 
President, in the chair.—On the geology of Northern 
Anglesey, by C. A. Matley ; with an appendix on the micro- 
scopic study of some of the rocks, by Prof. W. W. Watts. The 
strata which occupy the northern part of Anglesey have been 
the subject of much controversy, some geologists considering 
them (with the exception of a few patches in the extreme north) 
to be pre-Cambrian, while others maintain that they are of 
Bala age, and that they are an upward continuation of the 
black slates that everywhere appear to underlie them to the 
south. The author attacks this problem from its palzonto- 
logical as well as its stratigraphical side. The contortion, 
overfolding, cleavage, dislocation, and disruption which the 
rocks have undergone are described. Disruption is traced 
from its early stages into ‘‘crush-conglomerates.” Some of 
the disrupted rocks are Ordovician, and traces of ancient dykes 
have been found rent to pieces by the movement, which is 
stated to be post-Ordovician and pre-Carboniferous. The de- 
tached masses of limestone and the isolated ‘‘ quartz-knobs” 
of the northern complex are considered to be portions of strata 
which have suffered disruption in the same way as the thinner 
hard bands in the crush-zones. The appendix contains notes 
on some of the rocks from the Green series and the Ordovician 
system, the quartzites, and the crush-conglomerates.—On an in- 
trusion of granite into diabase at Sorel Point (Northern Jersey), 
by John Parkinson. In the early pages the general character of 
this intrusion is described. Following this general introduction, 
the characters of the granite are described in some detail ;_ then 
those of the diabase, formerly an ophitic dolerite. Details of 
structure of the granite in which absorbed basic material is 
present, and of the diabase into which acid material has per- 
meated, are dealt with: particular attention being directed to 
the great alteration which the diabase has undergone—this 
has frequently amounted to a total reconstitution. In conclu- 
sion, points of resemblance and of difference are noted between 
this district and others ; and an interesting slide from Alderney 
is described, showing the probable extension of such rocks in 
other directions. 
EDINBURGH. 
Royal Society, May 8.—Prof. Flint in the chair.—By re- 
quest of the Council, Mr. C. W. Andrews, of the British 
Museum, gave an account of his expedition to Christmas Island, 
with special reference to its geology. The island seems to be 
a raised atoll resting on a basis of volcanic rocks and Miocene 
limestones, which in places are some hundreds of feet thick. 
The rocks forming the highest parts of the island are for the 
most part dolomitised, and the most recent of the deposits 
found are beds of phosphate of lime, which cap some of the 
highest hills on the east and north sides. _ Formerly existing 
as a group of islets with a central lagoon, Christmas Island 
has undergone a succession of movements of elevation, evi- 
denced by the existence of a number of inland cliffs and ter- 
races. At present a narrow fringing reef is forming round the 
greater part of the coast. The fauna and flora are specially 
remarkable for the large number of species peculiar to the 
island. Specially interesting are the two forms of rats (the one 
being fitted for climbing trees, and the other for burrowing), 
six species of land-crab, two bats (one flying at midday), several 
forms of pigeon, and numerous sea birds. As regards the 
flora, there was no difficulty in understanding how the seeds 
had originally found a lodgment in the island. One important 
part of the work of the expedition was to make a collection of 
the fauna and flora before the settlement of the island led to 
the introduction of foreign species and the modification or 
destruction of the endemic forms. Sir John Murray, in em- 
phasising the importance of the scientific work carried out by 
Mr. Andrews, pointed out that Christmas Island was an illus- 
tration of how unexpectedly purely scientific inquiry led to a 
practical issue ; for it was in the course of his investigations 
