Marcu 7, 1907 | 
NA LODE 455 
EDINBURGH. 
Royal Society, February 4.—Dr. R. H. 
the chair.—The fossil Osmundacee: R. Kidston and 
D. T. Gwynne-Vaughan. The paper contained a de- 
scription of two new species of Osmundites, collected from 
the Jurassic of Otago, N.Z., by Messrs. Dunlop and Gibb, 
after whom they have been named. Osmundites Dunlopt 
differs from the hitherto described species in possessing a 
continuous ring of xylem which is not interrupted by 
the departure of the leaf-traces. In O. Grbbiana the 
xylem ring resembles that of the recent Osmundacee, 
and is broken up into a large number of separate strands. 
The structure of two other species, O. Dowkeri and 
O. skidegatrusis, was also described and compared with 
that of the new species. Their discussion of the bearing 
of the structure of the fossils upon the anatomy of the 
order led the authors to regard the osmundaceous stele 
as derived from an ancestral protostelic type with a solid 
central axis. It was consequently suggested that the 
Osmundacez were derived from the same ancestral stock 
as the Botryopteride.—The development of the anterior 
mesoderm and paired fin, with their nerves, in Lepido- 
siren and Protopterus: W. E. Agar. The pro-otic meso- 
derm is quite unsegmented. The material from which the 
eye-muscles are derived is, however, drawn from an ex- 
tended source, probably representing the three anterio1 
somites of van Wighe. A study of the conditions in these 
fishes lends support to the view of Gegenbaur as to the 
segmentation of the head in opposition to those of 
van Wighe. It seems probable that the latter’s fourth 
pro-otic somite represents a fused mass of segments to 
which the whole of the branchial region morphologically 
belongs. An extension of splanchic head structures back- 
wards in relation to trunk myotomes actually takes place 
in the ontology of these forms. The constrictor muscle 
of the pharynx is derived from two distinct sources, one 
splanchic, from the walls of the pericardio-peritoneal duct, 
the other somatic, from the occipital myotome y. A 
separation of the hypoglossal and brachial plexures is 
brought about by the greatly distended pronephros separ- 
ating the ventral processes of those myotomes which 
supply the hypoglossal and pectoral fin musculature re- 
spectively. The pectoral fin is situated in front of the 
myotomes which supply its mesoderm, and _ posterior 
myotomes are gradually ceasing to contribute to its 
development. The pelvic fin develops at the hind end of 
its innervation region. Its position is subiect to consider- 
able individual variation, but this is always accompanied 
by a corresponding variation in the position of the cloaca. 
—Scottish Tardigrada, collected by the Lake Survey : James 
Murray. Though found in Scotland nearly 150 years ago, 
the Tardigrada were totally neglected until recently the 
Lake Survey offered an opportunity for their study. 
In the paper a summary is given of all that is known 
about Scottish Tardigrada. The list contains forty-one 
species. In the Scottish lochs thirty-one species have been 
found. Most of these are of casual occurrence in lochs, 
only two or three species being normal inhabitants of 
water. About twenty species were noted in the Shetland 
Islands, a fact of great interest being the occurrence of 
a number of species hitherto known only from Arctic 
regions. A number of new species discovered had the 
same limited distribution, being known as yet only from 
Scotland and Spitsbergen or Franz Josef Land. Seven 
new species and four new varieties were described.—Arctic 
Tardigrada, collected by W. S. Bruce: James Murray. 
Richters had already noted twenty-four species of Arctic 
Tardigrada. Bruce’s collections on various expeditions 
vielded twenty-eight species, bringing the total number of 
known Arctic species up to forty. Three new species were 
described, and there were eight which had been recently 
discovered in Scotland. There were fourteen species 
common to Scotland and some part of the Arctic regions. 
Of the twenty-two species collected in Spitsbergen, twelve 
were new for that region. Franz Josef Land was virgin 
soil, and of the nineteen species found there, fifteen occur 
in Spitsbergen.—Prymnothonus Hookeri, Poisson pela- 
gique de l’Erebus et de la Terror retrouve par |’Expedition 
Antarctic Nationale Ecossaise: Louis Dolio. The fishes 
collected on the voyage of the Erebus and Terror were 
NO. 1949, VOL. 75 | 
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not all brought home in safety. The most interesting of 
these lost fishes were the Prymnothonus and the Page- 
todes. The latter, which is probably the same as _ the 
Cryodraco of the Belgian expedition, was eaten by the 
cat of the Terror. A figure of Prymnothonus Hookeri 
was copied from a sketch by Hooker and published in 
1841 by Richardson, who considered it to be a Murzenoid 
allied to the congers. The figure is reproduced by Gunther 
in the eighth volume of his catalogue of the fishes in the 
British Museum, and he follows Richardson in his de- 
scription. Later, in his ‘* Pelagic Fishes of the 
Challenger ’’ (1889), Giinther places Richardson’s  speci- 
men third in a series of four small fishes A, B, C, D, and 
says :—‘ I have no doubt that all these specimens repre- 
sent larval conditions of fishes belonging to Paralepis or 
Sudis or of genera allied to them. That they afl are 
stages of development of the same generic type of fishes 
is very improbable, but the second and third specimens 
may well be considered to be the same type, which pro- 
visionally may be designated by the name proposed for it 
by Richardson.’’ M. Dollo, on the other hand, does not 
consider the Challenger specimens A and B to have any- 
thing to do with Prymnothonus, and regards specimen D 
to be a mature specimen of Richardson’s fish. He gives 
a rectified diagnosis of trymnothonus Hookeri, Richard- 
son, from three specimens collected by the Scottish 
Antarctic Expedition, and places the fish in the family 
Paralepide, in accordance with Ginther’s indications. 
Paris. 
Academy of Sciences, February 25. — M. Henri 
Becquerel in the chair.—The president announced the death 
of M. Moissan, member of the section of chemistry, and 
gave a short account of his life-work.—Certain algebraical 
surfaces related to Abelian functions of the third kind: 
I.. Remy.—Remark on waves of shock. Application. to 
the explosive wave: M. Jouguet. For a wave of shock 
to be propagated, it is necessary that it should have a 
velocity higher than, or at least equal to, that of ordinary 
waves in the medium which precede it, and lower than, or 
at least equal to, that of the ordinary waves which follow 
it. Admitting this proposition, the author applies it to 
tiie interpretation of the phenomena of the explosive wave. 
—Some properties of the explosive wave: M. Crussard. 
—The influence of temperature on absorption in crystals. 
Magneto-optical phenomena at the temperature of liquid 
air: Jean Becquerel. At the temperature of liquid air 
the optical properties of crystals approach the properties 
of transparent vapours, the absorption bands contracting, 
forming a line spectrum. The author’s interpretation of 
these results is that the period of the proper movement 
of the electrons is not influenced by temperature in solid 
bodies, but that the damping, or the resistance to the 
particles in vibration, increases and decreases with the 
temperature. The magneto-optic phenomena exhibited by 
xenotime and tysonite at the temperature of liquid air have 
also been studied.—The theory of the formation of aven- 
turine copper glass: V. Auger. Experiments tending to 
show that the colour is due to the presence of copper 
silicate.—Ethyl lactyl-lactate: E. Jungfieisch and M. 
Godchot. A study of the products formed by the action 
of heat on ethyl (d+/) lactate. These are analogous to 
those obtained by heating lactic acid, but the mechanism 
appears to be different in the two cases.—The atomic 
weights, a function of the position which they occupy in 
the series of their increasing value: Adolphe Minet. 
The melting points and boiling points of aliphatic and 
aromatic hydrocarbons: Gustave Hinrichs. <A discussion 
of a recent paper of M. Tsakalotos.—The coagulation of 
the latex of caoutchouc and the elastic properties of pure 
caoutchouc: Victor Henri. The latex of india-rubber. is 
a negative emulsion, and its coagulation can be compared 
with the precipitation of negative colloids. A study of the 
conditions of coagulation leads to the conelusions that the 
coagulation of the latex by electrolytes is determined by 
the positive ions of the electrolytes, the structure of the 
coagulum varies with the nature and concentration of the 
bodies employed for the coagulation, a feeble coagulant pro- 
ducing a pulverulent or flocculent precipitate, an energetic 
coagulant an elastic clot with a reticular structure. The 
elastic properties of the india-rubber obtained depend 
