The idea of chemical structure, as founded on that of atomicity (or the equivalence of atoms), enables us to divide any molecule, whose chemical structure is known, into radicals. The number of ways in which this may be done increases with the complexity of the molecule. Each of these modes of division corresponds to a series of conceivable reactions, some of which have been observed. Any one of these series may be made the basis of classification; but it is obviously most convenient to select for this purpose the most characteristic reactions, and those which are common to such substances as form natural groups. In studying these, we find that each series implies the presence of a particular radical, within which the reactions in question take place. We may call such series of reactions the Generic reactions, and the corresponding radicals Generic radicals. These are sometimes residues of double decomposition, but very frequently this is not the case, and this may account for the fact, that the importance of these generic radicals has been very much overlooked.

Little Cumbrae and south Bute are the closest outliers of Early Carboniferous Clyde Plateau volcanic rocks to those forming the plateau itself, and the only ones with the potential to reveal how the volcanic succession of the plateau becomes attenuated westward beneath the Firth of Clyde. Closest links are to the Renfrewshire Hills Block of the plateau proper, where the Clyde Plateau Volcanic Formation attains its greatest thickness and widest extent.

Basal lavas in both outliers can be correlated to the lower part of the Strathgryfe Member of the Clyde Plateau Volcanic Formation (Viséan, Holkerian), which rests disconformably on the Clyde Sandstone Formation (Tournaisian, Chadian). Relative to the Renfrewshire Hills Block, this implies intervening overlap of three older members of the Clyde Plateau Formation and overstep of a varied sedimentary foundation. Higher lavas and pyroclastic accumulations in south Bute are correlative to the Misty Law Trachytic Member and upper part of the Strathgryfe Member. Thin lavas that cap the Renfrewshire Hills Block on its eastern flank probably never accumulated as far west as the present Firth of Clyde.

Southwestward from the Renfrewshire Hills, the Clyde Plateau lavas lose about two thirds of their 1000-m thickness in 25–30 km – a rate of thinning that implies they may extend no farther than the Sound of Bute or northeastern Arran.

In 1836, Mr Fox Talbot communicated to the Royal Society a paper “On the Optical Phenomena of certain Crystals” which he obtained by dissolving a crystal of Borax in a drop of somewhat diluted Phosphoric acid. When the acid and the salt are in proper proportions, “the field of view of the microscope is seen covered with minute circular spots, each of which is like a tuft of silk radiating from a centre, and is composed of a close assemblage of delicate acicular crystals forming a star.” Among these crystals are seen interspersed “a number of circular transparent bodies, which are tufts or stars of acicular crystals, in such close assemblage as to be in optical contact with each other, and to produce the appearance of a single individual.”

The Granophyric Quartz-dolerite is one of a number of intrusions having arcuate outcrops which are concentric with respect to Centre II, Ardnamurchan. It is composed of three rock types: porphyritic dolerite, aphyric dolerite and granophyre. The granophyre extensively net-veins the two kinds of dolerite. However, the development of the net-veining was only the last stage of its intrusive activity. Relationships between granophyre and aphyric dolerite are such as to indicate that at an earlier stage both were in a magmatic state at the same time; that is, they were intruded together, though movement of granophyre magma persisted after the aphyric dolerite had solidified. Evidence is presented to show that intrusion of the porphyritic dolerite was the first episode, and that this provided the host rock for the simultaneous intrusion of aphyric dolerite and granophyre. In its role as host rock, the porphyritic dolerite was at first incompletely crystallized, but for later intrusions it had consolidated. When both dolerites were solid they were net-veined by the granophyre.

The inner contact of the Granophyric Quartz-dolerite was formed by a later intrusion. The outer contact for much of its extent dips fairly gently outwards, and it would seem that where this is so intrusion was more nearly in a horizontal than a vertical sense. Locally, sheeted relationships between the three members of the Granophyric Quartz-dolerite, being gently inclined, support this conclusion. There are several possibilities as to the form the intrusion might have, and these are discussed.

It is generally believed that in mammals the impulse for cardiac contraction is conveyed from the atria to the ventricles by the atrioventricular bundle and its branches. This belief is mainly based on the A-V. dissociation which is found to follow experimental injury of the bundle. Since the bundle contains nerves, as well as specialized muscular elements, these experiments do not conclusively prove which structures, nerves or muscle, actually conduct the impulse. In the dog it has been previously shown that the right limb of the bundle is not usually accompanied by nerves, and in the present work the attempt was made by means of very small incisions to cut the muscle (Purkinje) fibres of the limb without damaging nerves in the ventricular septum, the effect on the electrocardiogram being noted. In 5 out of 38 perfused hearts of dogs the experiment was successful, and resulted in a significant delay in the contraction of the right ventricle relative to that of the left. The experiments also revealed that very considerable damage can be inflicted on the nerves in the ventricular septum without altering the electrocardiogram, so long as the limb itself is not injured. The results are regarded as providing direct evidence that the cardiac impulse in the dog is transmitted to the right ventricle by the muscular elements of the right limb of the bundle, and it is submitted that there would seem to be no valid reason for supposing that conduction throughout the A-V. bundle and its limbs is other than myogenic.

As the result of two visits to Orkney, in which he was accompanied by Mr B. N. Peach, he pointed out that the yellow sandstones of Hoy did not pass down conformably into the flagstones which form the basis of that island, but were separated from them by a marked unconformity. At the base, of the upper sandstones lay a series of contemporaneous lavas and ash beds, which were in all probability erupted, from certain ‘necks’ in the low-lying district at the foot of the Hoy Hills. These rocks he regarded as belonging to the upper Old Red Sandstone. The lower Old Red Sandstone consisted principally of a great thickness of flagstones, with which were interstratified beds of yellow and red sandstone, and occasionally of conglomerate. The fossils belonged exclusively to this lower series; and a table is given, compiled by Mr C. W. Peach, showing the distribution 9f fossil fishes in the lower Old Red Sandstone of Lake Orcadie, including those of Orkney so far as known at that time. As Sir Archibald Geikie anticipated, subsequent revision has necessitated “considerable pruning of the fossil lists.” The conglomerates around the granite axis of Stromness formed merely a local base, “due to the uprise of an old ridge of rock from the surface of the sheet of water in which these strata were accumulated,” and were presumably not on the same horizon as the thick conglomerates on which, in Caithness, the lowest flagstones rest. The sandstones interbedded with the flagstones in South Ronaldshay were regarded as in all probability the northward continuation of the similar rocks at Gill's Bay, Huna, and John o'Groats, on the south side of the Pentland Firth. From a geological point of view, the brief notice of the Old Red Sandstone of the Orkneys contained in this paper forms by far the most important contribution to the knowledge of the subject published up to that time.

The common association of mid-crustal migmatites with an upper-level granite pluton could indicate that the migmatites are a feeder zone for the pluton. If magma from a deeper level pervasively intrudes a high temperature metamorphic complex, most of the intruded magma would not freeze because of the prevailing temperature. The interaction between the magma and country rocks, which could include partial melting and crystallisation of the magma passing through, would modify magma to a more granitic composition, as found in the higher-level pluton.

The physical aspect of the magma transport through such a hot feeder zone is modelled by introducing a dimensionless melt transport (MT) number, which is the ratio of the rate of melt movement caused by the bulk flow of the entire mass (melt+solid) to that of porous media flow of melt only through the solid framework. The MT number is strongly dependent on the melt content of the melt-rich zone (MRZ), the diameter of the MRZ and typical particle size in the MRZ.

The ∼300-Ma, diatexitic, Lauterbrunnen migmatites (LM) in the Aar massif, Swiss Alps, may be such a feeder zone for the nearby 303-Ma Gastern granite (GG). The chemical and field evidence indicates that the LM formed by an intrusion of intermediate composition magma, which interacted with country rocks to produce a magma of GG composi

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.

The following work is based upon the magnificent collection of rock specimens made by Mr D. Ferguson during the expedition described in the foregoing paper. The number of these specimens is 210; and as many were collected in quadruplicate, it has been found possible to make up sets which have been presented to the British Museum (Natural History), the Royal Scottish Museum, Edinburgh, and the Sedgwick Museum, Cambridge. The most complete set is retained in the Hunterian Museum of the University of Glasgow.

Snowmelt modelling is of potential value in flood forecasting, reservoir management, and understanding stream acidification. It involves meteorological extrapolation, snowmelt calculation, meltwater routing, and snowpack depletion. A simple conceptual model using air temperature can reproduce the general pattern of daily streamflow in basins of >100 km2 but is prone to parameter instability. At a point scale and with the benefit of automatic weather station data the energy balance approach is superior to temperature index methods, but the roughness length parameter is again unstable in time and space. Even in a small (0·4 km2) basin this approach has to be coupled with an adequate flow routing model. Current research is comparing alternative models and data inputs in an intermediate-sized basin.

There are three distinct Silurian successions exposed in South Mayo and North Galway, western Ireland, of which the Louisburgh-Clare Island succession is the most northerly. It is separated from the adjacent Croagh Patrick succession by the Emlagh Fault. Three of the formations (Strake Banded, Knockmore Sandstone, Bunnamohaun Siltstone) in this 1·5 km Louisburgh–Clare Island succession had previously been interpreted as intertidal to offshore marine deposits. Almost all the facies present display characteristics of fluvial sedimentation and there is evidence for a contemporaneous volcanic centre to the west of the present outcrop. The exceptions are some grey laminated mudrocks with a fragmentary fauna which are interpreted as lacustrine and which show striking similarities to parts of the Silurian inliers in the central Midland Valley of Scotland. Despite these similarities the evidence for direct connection between western Ireland and Scotland is unproven. Within western Ireland correlations are hindered by uncertainties of the age of the Louisburgh-Clare Island succession and the age span of the adjacent Croagh Patrick succession.

At present our knowledge of the exotic genera of the aquatic Oligochæta is not very far advanced. During the last twenty years there has been a considerable accumulation of descriptions of exotic Earthworms, but the lower Oligochæta have been much less studied. The principal investigations into this group have been carried on by Eisen, who has made us acquainted with a number of interesting forms, belonging to the families Tubificidæ and Lumbriculidæ, from North America. Other naturalists, such as Leidy, have also dealt with the Oligochætous fauna of that country; but their papers have chiefly had for their object the discrimination of genera and species, and are not so much concerned with the description and delineation of anatomical structure. Beyond the series of papers published by the above-mentioned authors, we have only a few scattered memoirs by other writers upon exotic species of “Limicolous” Oligochæta.

Having recently been awarded, by the Government Grant Committee of the Royal Society, a sum of money to assist me in the investigation of the Oligochæta, I have been anxious not to limit myself to Earthworms, but to obtain as many specimens of the aquatic forms as possible.

In the progress of the Geological Survey of the South of Scotland, specimens referable to the genus Eoscorpius have been gradually accumulating. In 1876 J. Bennie, Fossil Collector to the Survey, obtained an example from the Coal-measures of Fife. Since then fragments have been disinterred by him and by A. Macconochie, also Fossil Collector to the Survey, from the Calciferous Sandstone series in the counties of Edinburgh, Berwick, Roxburgh, Dumfries, and Northumberland and Cumberland. It was not till the spring of last year (1880) that they began to be found in such a state as to necessitate a description of the fossils. In the summer of that year A. Macconochie obtained an almost entire example from the neighbourhood of Langholm, in Dumfriesshire. This year (1881) J. Bennie has secured several good though fragmentary specimens from the neighbourhood of Edinburgh, while A. Macconochie has sent in several from the counties of Berwick and Northumberland. In my capacity of Acting Palæontologist, I have had an opportunity of studying these remains, and by the permission of A. C. Ramsay, LL.D., F.R.S., Director General of the Geological Survey of Great Britain, and Professor A. Geikie, LL.D., F.R.S., Director of the Geological Survey of Scotland, I have been allowed to describe them.

Comparisons of the Caradoc assemblages with North American biofacies indicate that the Bardahessiagh Formation was deposited during a transgressive regime, which peaked with the presence of a typical Sericoidea association (member (II)). These diverse and exceptionally preserved faunas lived below the storm-wave base. The assemblages also contained a shallower water brachiopod component typical of transition zone environments or above, which may have been transported during periods of instability. A deep-water regime (BAs 4 to 4–5) through the Rawtheyan occurs with the deposition of the Killey Bridge Formation, which yielded a diverse brachiopod fauna including Bimuria, Chonetoidea and Christiania. The Rawtheyan assemblage also contains a shallower water component. Representatives of the deep-water Proboscisambon assemblage occur in middle parts of the Tirnaskea Formation. This distinctive low-diversity assemblage yields small, thin-shelled brachiopods including Dedzetina, Sericoidea, Protozyga and Proboscisambon. The upper parts of the Tirnaskea Formation yielded the low diversity, shallow water (BA 3) Hirnantia fauna, which is characterised by the presence of Eostropheodonta, which is a key form of the fauna, Dysprosorthis and the absence of Hirnantia. As a whole the changing brachiopod biofacies monitor environmental fluctuations, on part of the Laurentian margin, driven mainly by eustatic and tectonic events.

The influence of Size as a factor in the stelar morphology of the Filicales (2) and of some Primitive Plants (3) has already been discussed in the Proceedings of this Society. The aim of the present investigation is to determine by actual measurement to what extent Size may have acted as a causal factor in determining the structure and arrangement of the vascular system of Selaginella.

The general relationships of the caudal scales in Adpenser sturio and Acipenser ruthenus are considered together with a detailed description of the structure of the scales and corium in A. ruthenus, and a new staining method using purpurin counterstained with aniline blue for differentiating dermal structures in sections is described. A comparison of the caudal scales of sturgeons with those of palæoniscids indicates considerable agreement in form and arrangement between them. Evidence is presented to show that the caudal scales in sturgeons and palæoniscids are distinct from the general body covering of scales, and evidence points to a similar, though reduced, squamation in Lepidosteus and possibly in Polypterus. The importance of the caudal scales in protecting the internal organs in the epichordal lobe of the tail and the significance of the boundary between the body and caudal scales as a hinge for tail flexure is discussed.

British and Irish species of the trilobite family Trinucleidae are investigated by numerical taxonomie methods. Forty-five attributes are defined, relating mainlyto the dorsal surface of the cephalon, and several of them representing new concepts. Of the 106 described species from the British Isles, 31 are fully codable on the basis of topo types. An analysis is based on these species, together with 28 partly topotypically codable species and samples of 9 other species (undescribed, non-topotypic or non-British). The relations of the species are depicted in an ordination derived by principal components analysis of the interattribute correlation matrix and with superimposed minimal spanning tree. On the basis of the ordination most of the analysed species can be grouped into two subfamilies, Trinucleinae and Cryptolithinae (including Marrolithinae); thersites is excluded from Reedolithinae. Trinucleinae and Cryptolithinae are strongly differentiated on the y1 axis of the ordination. The two subfamilies show parallel evolution during the Ordovician in general cranidial attributes (e.g. increasing length, declination of fringe). In Trinucleinae the fringe also shows evolutionary changes (e.g. increases in numbers and regularity of arcs); in Cryptolithinae the fringe evolves very little. Ordination of the attributes is by non-linear mapping based on a distance matrix derived from the interattribute correlation matrix by the transformation (tanh-1|r|)-1. Lectotypes of 12 species are here selected: albidus Reed, ceryx Lamont, gibbsii Salter, girvanensis Lamont, hibernicus Reed, inconstans Whittard, persulcatus Reed, praeterita Reed, rhodesi Whittard, sortita Reed, subradiatus Reed and thersites Salter.

The nudibranchs collected by the Scottish National Antarctic Expedition comprise only six species, but these include two new and interesting genera.

The species are—

1. Notaeolidia gigas, gen. et spec. nov.

2. N. purpurea, sp. nov.

3. Tritonia appendiculata, sp. nov.

4. T. pallida, Stimpson.

5. Tritoniopsis brucei, gen. et sp. nov.

6. Scyllaea pelagica, L.

The Scyllaea was caught on the return voyage, in the Atlantic, 32° N., 33° W.; Tritonia pallida, off Dassen Island, forty miles north of Cape Town; Tritoniopsis brucei, off Gough Island, 40° 20′ S., 9° 56′ W.; and the three remaining species in Antarctic waters.

Subaerial lavas and intercalated sediments crop out on the islet of Glas Eilean and the Black Rock skerries in the Sound of Islay between Islay and Jura. The visible succession is c. 120 m thick and is traceable c. 2 km along strike (NNW–SSE). The lavas are alkali olivine-basalts containing olivine ± plagioclase and augite phenocrysts. Decreasing Mg, Cr and Ni upwards, coupled with decreasing average flow thickness and increasing amounts of inter-flow sediment, suggest progressively waning volcanic activity marked by decreasing ascent rates and greater degrees of differentiation. K-Ar dating on one sample gave an early Permian age of 285 ± 5 Ma. It is inferred that the lavas erupted from an isolated basalt volcano situated on a NNW–SSE trending fracture, associated with a narrow developing half-graben within the Dalradian metasediments. The tectonism and magmatism is inferred to be related to the ‘Clyde Belt’ of fault-bounded basins extending from Cheshire to the Little Minch.

A comprehensive analysis of early dinosaur relationships raised the possibility that the group may have originated in Laurasia (Northern Hemisphere), rather than Gondwana (Southern Hemisphere) as often thought. However, that study focused solely on morphology and phylogenetic relationships and did not quantitatively evaluate this issue. Here, we investigate dinosaur origins using a novel Bayesian framework uniting tip-dated phylogenetics with dynamic, time-sliced biogeographic methods, which explicitly account for the age and locality of fossils and the changing interconnections of areas through time due to tectonic and eustatic change. Our analysis finds strong support for a Gondwanan origin of Dinosauria, with 99 % probability for South America (83 % for southern South America). Parsimony analysis gives concordant results. Inclusion of time-sliced biogeographic information affects ancestral state reconstructions (e.g., high connectivity between two regions increases uncertainty over which is the ancestral area) and influences tree topology (disfavouring uniting fossil taxa from localities that were widely separated during the relevant time slice). Our approach directly integrates plate tectonics with phylogenetics and divergence dating, and in doing so reaffirms southern South America as the most likely area for the geographic origin of Dinosauria.