A Monthly Review of Scientific Progress.

In addition to Notes and Comments on the progress of Natural Science, brief Reviews of Current Literature, Obituary Notices, and News of Universities, Museums, and Societies, the last four numbers of this Journal comprise the following specially contributed Articles :

No. 15, May, 1893.

I. Natural Selection and Lamarckism. By Wm. Platt Ball.

II. Biological Theories. IV. Supposed Auditory Organs. By C. Herbert Hurst, Ph.D.
III. The Fruit-Spike of Calamites: A Chapter from the History of Fossil Botany. By
Thomas Hick, B.A., B.Sc.

IV. The Succession of Teeth in Mammals. By Miss E. C. Pollard, B.Sc.

V. The Recapitulation Theory. A Rejoinder. By C. Herbert Hurst, Ph.D. VI. Climate and Floral Regions in Africa. By G. F. Scott Elliot, M.A., B.Sc. VII. The Moas of New Zealand. By Henry O. Forbes, F.R.G.S.

No. 16, June, 1893.

I. Flowers in the Guiana Forest. By James Rodway, F.L.S.

II. Biological Theories. V.-Suggestions as to the True Functions of Tentaculocysts," "Otocysts," and Auditory Sacs." By C. Herbert Hurst, Ph.D.

III. Naegeli's Experiments on Living Cells. By Miss A. L Smith.

IV. Some Extinct Sharks and Ganoid Fishes. By A. Smith Woodward, F.L.S.

V. Notes on Warning and Protective Colour in Lepidopterous Larvæ. By Miss Lilian J. Gould.

VI. Cannibalism among Insects. By Carl Berg, Ph.D.

VII. The Classification of Arachnids. By George H. Carpenter, B.Sc.

VIII. The Great Barrier Reef of Australia.

No. 17, July, 1893.

I. Recent Researches on Plant Nutrition. By J. Percival, M.A., F.C.S
II The Respiration of Birds. By F. W. Headley, M.A., F.Z.S.

III. Observations on Certain Marine Animals. By James Hornell.

IV. Recent Progress in Conchology. By B. B. Woodward, F.R.M.S.

V. The Museums of Public Schools. I.-Charterhouse. By Oswald H. Latter, M.A.

VI. The Surface of the Moon. By Professor G. K. Gilbert, Ph.D.

VII. Antarctica: A Supposed Former Southern Continent. By Henry O. Forbes, F.R.G.S. VIII. On the Work of Glaciers. By Rev. A. Irving, M.A., F.G.S.

IX. Professor Huxley on Evolution and Ethics.

No. 18, August, 1893.

I. Rainfall and the Forms of Leaves. By Miss Annie Lorrain Smith.

II. On the Zoo-Geographical Areas of the World, illustrating the Distribution of Birds. By R. Bowdler Sharpe, LL.D., F.L S.

III. Earthworms and the Earth's History. By F. E. Beddard, M.A., F.R.S.

IV. Some Useful Methods in Microscopy. By E. A. Minchin, M.A.

V. Recent Additions to our Knowledge of the Eurypterida. By Malcolm Laurie, M.A., F.L.S.
VI. Supposed Fossil Lampreys. By A. Smith Woodward, F.L.S.

VII. The Origin of Monocotyledonous Plants. By A. B. Rendle, M.A., F.L.S.
VIII. The Recapitulation Theory in Biology. By S. S. Buckman, F.G.S.
IX. Professor Blake "On the Bases of the Classification of Ammonites."

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SOME NEWLY-HATCHED SPECIMENS

AND A

LATE EMBRYO OF OPISTHOPHTHALMUS.

BY

MALCOLM LAURIE, D.Sc., B.A., F.R.S. E., F.L.S.

Physical Society of Edinburgh, Vol. XIII.]

XII. Some Newly-Hatched Specimens and a late Embryo of Opisthophthalmus. By MALCOLM LAURIE, D.Sc., B.A., F.R.S.E., F.L.S., Professor of Zoology in St Mungo's College, Glasgow. [Plate IV.]

(Read 19th February 1896.)

While examining some of the Arachnida in the British Museum, my attention was drawn by Mr Pocock to two sets of newly-hatched Scorpions, which showed certain peculiarities of structure. Both lots belonged to the South African genus Opisthophthalmus, one being the young of O. capensis (Herbst) and the other the young of an undetermined species. Through the kindness of Dr Günther and Mr Pocock, I was able to examine some of the specimens minutely, and to cut a series of sections through one.

The peculiarity which strikes one at first sight is the presence of two long processes growing from the prosomatic region. The more prominent of these arises in front of the mouth and projects forward like a proboscis (Figs. 1-3, a). It has a length greater than that of the carapace, and is found in section to be a tube filled with trabecular tissue, and probably also containing blood-vessels. Though arising immediately in front of the mouth, it has no connection either with the oesophagus or with the powerful sucking muscles. The cavity appears to communicate with the general body space, but is not easily traced among the complex structures of this region.

The other process arises from the dorsal surface of the carapace. In O. capensis (Fig. 3, b) its point of origin is close behind, indeed almost between, the median eyes. It is bent forward, and lies along the carapace, projecting slightly beyond the front margin. In the other species (Fig. 2) the process arises about 2 mm. behind the eyes, and lies directed backwards in a groove in the carapace. It fits so closely into this groove that it might easily be overlooked. It is shorter (measuring about 1 mm.) in this species than in O. capensis, and does not reach the hind margin of the carapace. This