1. It may be taken as conclusive that the final distribution of stress at rupture point in a member subjected to an external bending moment is a rectangular one, unless where the cohesion of adjacent layers is not sufficient to withstand the shear induced by the resisting moment of the section.

2. That, provided shear does not take place, the neutral axis moves always to the position which reduces the summation of the tensile and compressive stress areas, across a section, to the equilibrant of the external forces. (In the case of a beam this reduces to zero; in that of a hook, at the principal section to the suspended weight.)

3. That the total resisting moment of these stresses must be equal to the external bending moment as measured to the neutral axis at rupture point, but that these balancing moments do not differ materially from those measured to an axis obtained by dividing the sectional area into tensile and compressive stress areas which are in inverse proportion to the magnitude of their respective ultimate direct stresses.

The advantage of these formulæ are important. It is possible to indicate with certainty the magnitude of the load which will cause rupture in a beam or a hook provided there is known the point of application or the effective arm of the load, the cross-section of the beam or hook, and the breaking strengths of the material when subjected to the different forms of direct loading.

In a recent paper (Gordon, 1938) reasons were given for the belief that semi-arid conditions prevailed during Lower Carboniferous times in the neighbourhood of North Berwick, East Lothian. The evidence was opposed, in a measure, to that advanced by Mr George Barrow in the East Lothian Memoir (1910) to substantiate the same position. He had relied on the absence of fossils as part proof; but, in point of fact, fossil plants have been obtained in abundance from the actual bedded ashes of Oxroad Bay that he considered (a) to be unfossiliferous, and (b) to have been formed in a manner similar to beds on the Springbok Flats of the Transvaal. The plants that have now been obtained showed xerophytic features, and, consequently, a semi-arid climate was proved on positive evidence. Other positive evidence of a lithological character was also presented in confirmation (Gordon, 1938, pp. 352, 353).

The first petrographic description of the rocks of South Georgia was given by H. Thürach in 1890, as part of the results of the German Scientific Expedition to that area of 1882–83. He described the rocks as clay-slates interstratified with phyllite and phyllite-gneiss, with quartz-phyllite, calc-phyllite, and quartzite-slate. He also mentions a great development of interbedded schalsteine or diabase tuffs, and describes a rolled pebble of “korniger gneiss.” His phyllite-gneiss is said to contain tourmaline, apatite, and andalusite. He emphasises the great crushing and disturbance the rocks have undergone.

During the Scottish Antarctic Expedition of 1892–93 Dr W. S. Bruce secured fœtuses of Stenorhynchus leptonyx and Lobodon Carcinophaga, and on his return passed them over, with other material, to Professor D'Arcy W. Thompson for the Zoological Museum of University College, Dundee. While some of the material has unfortunately been lost sight of during these twenty-one years, one specimen, viz. that of a fœtus of Stenorhynchus leptonyx, was still in existence, and was returned by Professor D'Arcy Thompson to Dr Bruce, who in turn asked me to examine and report upon it. Furthermore, during the voyage of the Scotia embryos of Leptonychotes weddelli were obtained by the Scotia naturalists, and these were passed on for description to Professor Waterston, at that time in the University of Edinburgh. It is on this material that the present monograph is based.

The pharmacological action of tetra-ethyl-ammonium chloride has been investigated to a limited extent by Tillie, Santesson and Koraen, Tappeiner, Boehm, and Höber and Waldenberg, in the course of other researches. Tillie, and Santesson and Koraen, describe its action on frogs; Tappeiner merely states that it has no paralysing effect on the respiration of the rabbit; Boehm, and Höber and Waldenberg, refer only to its effect on the isolated frog's muscle. The descriptions of the action of the iodide, which has been investigated by Jordan, Brunton and Cash, Rothberger, Jacobj and Hagenberg, and Barger and Dale, in the course of other work, are also somewhat meagre. Brunton and Cash, and Jacobj and Hagenberg, describe its action on frogs, and Brunton and Cash its action on rabbits; but Jordan merely says that it produces on frogs a curare-like action but no muscarin effect, and Barger and Dale only state that it has no sympathomimetic action. The investigation of Rothberger was limited to its antagonistic action towards curarin.

I have no information regarding the gametophyte, nor have I examined the structure of axis and leaf in young plants. It must therefore remain to be seen what light such data may throw upon the problem of the phyletic place of Deparia Moorei. The nature of the stele, the leaf-trace, and the venation, in very young plants, would also present points of value. But it will be at least evident that the vascular system of the axis is, in mature plants, of an advanced type, and it may reasonably be affirmed that the marked variability in the degree of dictyostely is an index of an inherent plasticity. It seems reasonable to suggest that the reductions in size, and simplification of structure in the direction of solenostely shown in fig. 40, is related to the cultural conditions. The plant from which the material was derived had lost ground both in size and healthiness of its leaves.

The study of Organic Form, which we call by Goethe's name of Morphology, is but a portion of that wider Science of Form which deals with the forms assumed by matter under all aspects and conditions, and, in a still wider sense, with Forms which are theoretically imaginable.

The study of Form may be descriptive merely, or it may become analytical. We begin by describing the shape of an object in the simple words of common speech: we end by defining it in the precise language of mathematics; and the one method tends to follow the other in strict scientific order and historical continuity.

In a recent publication on the cyclic variations of the vascular architecture of the uterus of the guinea-pig (1940) we recorded that antimesometric hyperæmia is a regular and essential characteristic of the uterine changes which occur during heat, and commented on its significance as a factor influencing antimesometric implantation in this animal.

The specimens described in this paper were collected by Dr J. H. Harvey Pirie, B.Sc, M.B., geologist to the Scottish National Antarctic Expedition, during a short visit paid to Gough Island on the homeward voyage of the Scotia from the Antarctic seas in 1904. The island is not often visited, and the only previous account of the rocks is by Professor L. V. Pirsson, who described a series of beach pebbles collected by the captain of a whaling vessel. Among those Professor Pirsson noted two varieties of basalt, trachytic tuffs, and a trachytic obsidian carrying olivine, and shown by chemical analysis to be of phonolitoid type.

With the exception of a small fragment of limestone, the rocks in the Scotia collection are all igneous. They were obtained in the neighbourhood of the usual landing-place, the mouth of a small glen on the eastward side of the island. They include soda trachytes, trachydolerites, basalts, an essexite, and tuffs.

1. The active ingredient of the poison of the Abor and Mishmi poisoned arrows is, in some of them, aconite, and, in others, croton oil. The former, apparently, is generally used by the Mishmis, and the latter by the Abors.

2. Although sufficient botanical materials have not been obtained to identify the species of aconite, the nature of the pharmacological action suggests that the species is one containing relatively more pseudo-aconitine than aconitine and, therefore, more resembling Aconitum ferox and A. heterophylloides than A. Napellus.

3. The arrow-poisons containing aconite were found to be much more lethal in warm-blooded animals than those containing croton; but the aconite-poisoned arrows that were examined carried usually too little aconite for a single arrow to produce death in man, even if the whole of the poison should be quickly absorbed.

4. The arrow-poisons containing croton, on the other hand, were found to be incapable of producing death in warm-blooded animals by the absorption of the poison into the circulation, and could do so only tardily by rendering the animal more susceptible to septicæmia, following inflammatory and even necrotic changes in the tissues into which the poison had been inserted.

5. While thus relatively inert in warm-blooded animals, and presumably, therefore, in man, the croton arrow-poison is extremely toxic in cold-blooded animals, being for them one of the most lethal of poisons, readily absorbable into the circulation and producing irritation and hæmorrhages in parts remote from the locality of insertion, and the latter, especially, in the alimentary canal. Remote effects may be produced even without any obvious evidence of local irritation in the place into which the poison has been inserted. These remarkable peculiarities in the action of the Government of India arrow-poison are reproduced by its ether extract and by the oil of Croton Tiglium.

6. Excepting failure to cause general action in warm-blooded animals, it is interesting to note that in many of their important effects, croton arrow-poisons as well as croton oil reproduce the effects of viperine venoms.

Chironomid larvæ for a long time have been known to inhabit the brackish pools around the coast, but there are few published records of their life-histories and habits, and in many cases they cannot be correlated with their imagines. This applies equally to the fresh-water types.

The greater part of the systematic work on the Chironomidæ deals with the imagines, and much confusion exists regarding the nomenclature of species, which most authorities admit cannot be rectified until the early stages have been recorded.

The Polychæte family Scalibregmidæ comprises seven genera, the limits and interrelationships of which are, however, still imperfectly known. The present paper results from a detailed study of one of these genera, a new species of which is described, chiefly from a specimen collected in Scotia Bay, South Orkneys, and entrusted to me for examination by Dr W. S. Bruce.

Description of the Specimen Collected in Scotia Bay, South Orkneys.: This specimen, the only Scalibregmid found by the Scottish National Antarctic Expedition, was dredged on a stony bottom in ten fathoms at Station 325, in Scotia Bay, South Orkneys (lat. 60° 43′ 42″ S.; long. 44° 38′ 33″ W.), in August 1903.

The worm, which is yellowish brown in colour (in alcohol), is 19 mm. long. The anterior portion is broad; the maximum breadth, 3 mm., is reached about the level of the 10th segment; from this region the worm tapers gradually to the anal segment. The dorsal surface of the worm is strongly convex; the ventral surface is flattened, and there is a well-marked depression which extends along the mid-ventral line from the 2nd chætiferous segment almost to the anus.

This study was begun in 1936 primarily as an attempt to work out the life-history of the Salmon gill-maggot Salmincola salmonea (L.), a common and widespread copepod parasite of the Atlantic Salmon (Salmo salar). At that time the adult female stage only was known, although this had been reported in Scotland as early as 1766 on a kelt salmon and had been included by Linnæus among his Vermes. It was not, however, until 1939, after three years of field work, that a complete series of the stages in the life-history of the parasite had been collected and the story began to take shape. During this time not only were parasites collected, but a quantity of statistical and observational data was accumulated bearing both on the parasite. and its host. Much of this referred to conditions in the estuary, a part of the common background of the two animals which was soon recognised to be a critical region for both. Consequently special attention was given to parasitised fish from this region, and this led to a widening of the scope of the investigation to include a consideration of the habitats and interrelations of gill-maggot and fish, indicated by the term “ecology” in the title.

The sponges in the following report were collected in the North and South Atlantic during the Scotia's voyages to and from the Antarctic regions in the years 1902–1904.

All the sponges in the collection were obtained off the south-west coast of Cape Colony, with the exception of five well-known species which were taken off St Helena, the Cape Verde Islands, and the Princesse Alice Bank. Only one specimen was dredged in deep water, namely, in 350 fathoms off the Princesse Alice Bank, while the remainder were taken between tide-marks to a depth of 30 fathoms.

The collection contains thirty-five species, of which fifteen are described as new.

To complete the list of sponges obtained by the Scotia in Atlantic waters, mention may be made here of one species which is not contained in this report. This species, Cladorhiza thomsoni, dredged in deep water between Gough Island and the Cape of Good Hope, has been described by Professor Topsent (24 and 25). It was taken at Station 468, 39° 48′ S., 2° 33′ E., depth 2770 fathoms.

The five species above referred to, Leucandra crambessa, Aphrocallistes beatrix, Tethya lyncurium, Chondrosia plebeja and Chondrosia reniformis, call for no special remark. They have all been previously obtained in, or fairly near, the areas for which they are here recorded.

During the last few years the distribution of the macrofauna, and to a less extent the microfauna, of the intertidal soils of the shores of Britain has received considerable attention and the principle that the species show a zonation with maximum densities at certain levels is now well established. The extensive studies of Elmhirst (1931) and of Stephen (1928, 1929, and 1930) on the fauna of the sandy and muddy areas of numerous Scottish bays has laid the foundation for much further work in this area. Pirrie, Bruce, and Moore (1932) have described the zonation of the fauna in the intertidal sand of Port Erin bay. Alexander, Southgate, and Bassindale (1935) refer to the fauna of the sand at the mouth of the River Tees, but mainly from the point of view of comparison with the fauna of the estuary. Crawford (1937 a and b)gives notes on the distribution and habits of certain intertidal species in sandy bays and estuaries in west England and south Wales. Rees (1939) has surveyed in outline, as part of a study of the interstitial sand copepods, the macrofauna of some sandy bays in north Donegal. Spooner and Moore (1940) have given a detailed description of the zonation of the species in the estuarine muds of the Tamar. A part from the above, reference must be made to two intensive studies on the soil fauna of the eastern shores of the North Sea, namely, that of Thamdrup (1935) on Danish shores and of Wohlenberg (1937) on certain bays on the island of Sylt. A general discussion of the ecological problems of sand, mud, and algal environments is given by Eemane (1933), based on the macrofauna and microfauna of Kiel bay. He reaches the conclusion, based on the number of species which occur in each environment, that the macrofauna of sand is comparatively poor compared with mud.