This paper reviews the changing environments, developing landforms and terrestrial stratigraphy during the Early and Middle Pleistocene stages in Scotland. Cold stages after 2.7 Ma brought mountain ice caps and lowland permafrost, but larger ice sheets were short-lived. The late Early and Middle Pleistocene sedimentary record found offshore indicates more than 10 advances of ice sheets from Scotland into the North Sea but only 4–5 advances have been identified from the terrestrial stratigraphy. Two primary modes of glaciation, mountain ice cap and full ice sheet modes, can be recognised. Different zones of glacial erosion in Scotland reflect this bimodal glaciation and the spatially and temporally variable dynamics at glacier beds. Depths of glacial erosion vary from almost zero in Buchan to hundreds of metres in glens in the western Highlands and in basins both onshore and offshore. The presence of tors and blockfields indicates repeated development of patches of cold-based, non-erosive glacier ice on summits and plateaux. In lowlands, chemical weathering continued to operate during interglacials, but gruss-type saprolites are mainly of Pliocene to Early Pleistocene age. The Middle Pleistocene terrestrial stratigraphic record in Scotland, whilst fragmentary and poorly dated, provides important and accessible evidence of changing glacial, periglacial and interglacial environments over at least three stadial–interstadial–interglacial cycles. The distributions of blockfields and tors and the erratic contents of glacial sediments indicate that the configuration, thermal regime and pattern of ice flow during MIS 6 were broadly comparable to those of the last ice sheet. Improved control over the ages of Early and Middle Pleistocene sediments, soils and saprolites and on long-term rates of weathering and erosion, combined with information on palaeoenvironments, ice extent and sea level, will in future allow development and testing of new models of Pleistocene tectonics, isostasy, sea-level change and ice sheet dynamics in Scotland.

The numerical taxonomic analysis of encrinurine trilobites by Temple and Tripp (1979) is extended to 28 described Chinese species, 35 other Chinese samples, and 13 non-Chinese species, in addition to 56 species analysed previously. The 132 entities are coded for 34 cranidial and pygidial attributes, and are ordinated on the eigenvectors of the interattribute correlation matrix for 32 attributes. Chinese material falls into four clusters informally compared with Coronocephalus, Kailia, Encrinuroides and Encrinurus. The Encrinurus-like Chinese species occur mainly in Northern China and have links with non-Chinese species.

The immense amount that has been written on the subject of dew renders it extremely difficult for one to state anything regarding it which has not been previously expressed in some form. It has been examined over and over by minds of every type, and from every point of view; so that every possible explanation of the different phenomena seems to have been given, and so many passing thoughts recorded, that from the literary point of view the whole subject seems exhausted. As a necessary result, these different treatises are in many respects contradictory; and it would be quite impossible to construct anything like a consistent explanation and account of our subject, from the very voluminous writings of those who have treated it from the purely literary point of view, and whose ideas have been evolved from their inner consciousness, according to what seemed to them the fitness of things, and without questioning nature as to the truth of their conclusions. On the scientific side of the subject, however, the writings are not so voluminous, and additions to it are still required to enable us to determine which of the many conflicting opinions are correct.

In the year 1903 Mr Macconochie made an interesting collection of fossil fish-remains from beds of Lower Carboniferous age exposed on the seashore near Gullane, in East Lothian, which were submitted to me for determination by the Director of the Geological Survey. Accordingly, I prepared a preliminary account of these remains, which was published in the Summary of Progress for the year above mentioned.

The collection of Nereidæ brought home by the Scotia proves to be of considerable interest. As other expeditions have indicated, the family is but poorly represented in the antarctic or sub-antarctic regions; and although a large number of specimens were collected at the South Orkney Islands, these have all proved to belong to one species, N. kerguelensis M'Int. No nereids were obtained at any of the deep-water stations farther south—the family being decidedly littoral in its range.

The chief interest, however, lies in the material collected so assiduously throughout the vessel's wanderings. Six other species were obtained, including one from the Falkland Islands, hitherto undescribed.

The theory of the knotting of curves, except for a few elementary theorems due to Listing, was entirely neglected until Tait was led to a consideration of knots by Sir W. Thomson's (Lord Kelvin's) work on the Theory of Vortex Atoms. He attacked chiefly the problem of constructing knots with any number of crossings, and obtained a census of the knots of not more than ten crossings. Those knots which exhibit a special kind of symmetry—the amphicheiral knots—offer certain points of interest.

The 119 subsolids (marked ss) and the 244 unsolids (marked us), of these unifilars are here arranged in lists according to their flaps. Fe is the number of flaps of e loops upon a knot; and the headings of the lists, as, e.g.10I, F2 = 1, F1 = 3, describe so far all the knots in the lists. Thus in 10I each has one 2-ple flap and three single ones. After the number in the list comes always the base on which the knot is constructed by the rules of my paper, XVII. in vol. xxxii. part ii. of the Trans. R. S. E.; and the reader who has that paper before him will find it easy to draw any knot on its base, nearly always there figured, by the first given flap, which is the leading one of the knot described; thus in 10I the first written flap is the double one, and in 10P, F3 = 1, F1 = 2, it is the triple one. The leading flap of a subsolid is always followed by a colon.

Alexander Wilson, M. D., late Professor of Practical Astronomy in Glasgow College, was a younger son of Patrick Wilson, town-clerk of St Andrew's, and was born there in 1714. He was very young when his father died, and was afterwards brought up by the care of his mother, Clara Fairfoul, a person much respected for her prudence, virtue, and piety.

Having received the usual education at the different schools, he entered to the College of St Andrew's, where he made great proficiency in literature and the sciences, and, after completing a regular course of studies, was admitted to the degree of Master of Arts in his 19th year.

The lower Mississippian Ballagan Formation of northern Britain is one of only two successions worldwide to yield the earliest known tetrapods with terrestrial capability following the end-Devonian mass extinction event. Studies of the sedimentary environments and habitats in which these beasts lived have been an integral part of a major research project into how, why and under what circumstances this profound step in the evolution of life on Earth occurred. Here, a new palaeogeographic map is constructed from outcrop data integrated with new and archived borehole material. The map shows the extent of a very low-relief coastal wetland developed along the tropical southern continental margin of Laurussia. Coastal floodplains in the Midland Valley and Tweed basins were separated from the marginal marine seaway of the Northumberland–Solway Basin to the south by an archipelago of more elevated areas. A complex mosaic of sedimentary environments was juxtaposed, and included fresh and brackish to saline and hypersaline lakes, a diverse suite of floodplain palaeosols and a persistent fluvial system in the east of the region. The strongly seasonal climate led to the formation of evaporite deposits alternating with flooding events, both meteoric and marine. Storm surges drove marine floods from the SW into both the western Midland Valley and Northumberland–Solway Basin; marine water also flooded into the Tweed Basin and Tayside in the east. The Ballagan Formation is a rare example in the geological record of a tropical, seasonal coastal wetland that contains abundant, small-scale evaporite deposits. The diverse sedimentary environments and palaeosol types indicate a network of different terrestrial and aquatic habitats in which the tetrapods lived.

Agnostid trilobites are described from the Lower Ordovician (Oelandian Series) of Öland, Östergötland, Västergötland and Närke, southern Sweden. In addition, a few agnostids are described from the Ceratopyge Limestone (upper Tremadoc) of Scania (Skåne), the southernmost province of Sweden. 24 species (of which Galbagnostus nericiensis is new), assigned to four genera, are described or discussed. Species of Geragnostus and Arthrorhachis dominate numerically. Also recorded locally are species of Galbagnostus and Leiagnostus. Most species have a markedly restricted vertical distribution, and many species appear to have a sufficiently short range to be of value in stage- and zone-level correlation. Agnostids are represented almost throughout the Lower Ordovician of southern Sweden, but they have not been recorded from the Tremadocian “Dictyonema” and Ceratopyge Shales, nor from the upper Holen Limestone (upper Kundan Stage). In the Ordovician of Baltoscandia, agnostids are largely restricted to the Central Baltoscandian Confacies Belt; they are very rare or absent in the adjacent belts to the east and in the graptolitic shales of the Scanian Confacies Belt.

The mineralogical determination of those species, the chief constituent of which is Manganese, has been for a long time destitute of that precision at which other species had long arrived, whose chemical constitution was better known. Two years ago I published, in a memoir “On the Crystalline Forms and Properties of the Manganese-Ores,” the most accurate information I could then collect, partly from some works on mineralogy, partly from my own observations. In the general descriptions which I propose giving here for the mineralogical illustration of Dr Turner's account of their chemical properties, I have availed myself of the corrections given in the translation of the same paper in Poggendorff's Annals by Professor Gustavus Rose, who has corrected or verified the angles given, and compared them again with nature; so that the statements have gained a considerable accession of authority. I have added the description of that species, which consists of the anhydrous peroxide of manganese, and which, from the difference of its properties from all the rest, whatever may be the mode of its formation, should be considered as a species of its own.

The task of examining and determining the fine series of lamellibranchs collected by Mrs R. Gray in the Girvan district, from rocks of Llandeilo, Bala, and Llandovery age, has been no light one. In the first place, the literature of the subject is very scattered, and is chiefly to be found in the various reports of the Geological Surveys of the different States of North America and Canada. The work of British palæontologists is to be found in the publications of the Geological Survey and in various periodicals, but nothing systematic has been attempted before in this country, although Sowerby described and figured, in an appendix to Murchison's Silurian System, all the known species. Under these circumstances there has been the greatest difficulty in studying original types, many of which are Swedish or North American.

Major and trace element, including REE, analytical data are used as bases for interpreting the petrogenesis of the major igneous components of the northern part of the Ballantrae complex which occurs in the southwestern part of the Midland Valley of Scotland. Most of the peridotite, now serpentinised, is similar to ultramafic rocks in other ophiolite complexes. Mean crystallisation conditions, determined on the basis of co-existing orthopy-roxenes and clinopyroxenes for the dominant peridotite and minor pyroxenite were 1060 (±60)°C—20 (±2) kb and 1240 (±89)°C—25 (±25) kb, respectively. These rocks, of mantle provenance, have compositions consistent with being residues after the extraction of 20–30% of tholeiitic material from the mantle. The presence among them of a rock whose REE contents indicate that it is a plagioclase peridotite, point to the tectonic incorporation of the products of a high level magma chamber.

The mafic parts of the complex have tholeiitic characteristics and developed between 1300° and 1100°C. They do not represent primary mantle melt but fractionated material. Clinopyroxene was the main fractionating phase and more than 10% fractional crystallisation is indicated with increase from gabbros, through beerbachites (metadolerites) of a sheeted dyke complex and pillow lavas, to microgabbros and pyroxene diorites. Biotite diorites and trondhjemites represent the most fractionated products, the latter having affinities with ophiolitic plagiogranites.

The beerbachites of the sheeted dyke complex do not all represent the same stage of fractionation. The pillow lavas have REE patterns similar to rocks found in marginal basins but are markedly different from pillow lavas from the Highland Border Complex in Arran, near the northern margin of the Midland Valley.

That phase of the nucleus just preceding the heterotype mitosis, and which was first called Synapsis by Moore (1895), has come to be regarded as an important and critical period in the life-cycle. It was called synapsis because of the apparent condensation and contraction of the chromatin at one side of the nuclear cavity. This discovery at first received scant support, the synaptic contraction being considered by many investigators to be nothing more than an artifact—an artificial contraction caused by imperfect fixation. In 1897, however, Moore's discovery was confirmed by Miss Sargant, who not only observed it in fixed material, but also found it in the living pollen-mother-cells of Lilium.

The Psilotaceæ constitute one of the most interesting of existing Pteridophyte groups. This interest is mainly due to their phylogenetic isolation. They are perhaps the most isolated of existing types—showing no close affinity to other Pteridophytes. They are very highly specialised in their anatomy, habit, and habitat, and limited to a comparatively narrow geographical distribution. They include two probably monotypic genera—Tmesipteris and Psilotum—which are closely related. Although both genera are limited to the tropics and sub-tropics, Psilotum has a much wider distribution than Tmesipteris. The latter is confined to the South Sea Islands, Australia, New Zealand, and parts of Polynesia. Up till recent years they have been classed with the Lycopodiales, but this has been more a matter of convenience than an indication of close relationship, and has only served as a temporary classification until more knowledge has been obtained regarding them. The peculiar nature of these plants, as shown in their structure and in their habitat, suggests that they are highly specialised remnants of a much larger group which has practically become extinct. Recent inquiry into the structure of the sporophyte of both plants has made this much more than a suggestion. As a result of the careful investigations of Scott (1908), Boodle (1904), Bower (1894-1908), Ford (1904), and others, there has been a marked tendency to remove the Psilotaceæ from their temporary position among the Lycopodiales and associate them with the extinct Sphenophyllales. Scott (p. 631) states that it seems best to regard the Psilotaceæ as forming a class of their own, the Psilotales, under the main division Sphenopsida—their closest affinity under this class being the Sphenophyllales. This probable affinity of the Psilotaceæ to such an ancient and long extinct race as the Sphenophylls, and the great uncertainty of their relationship to other existing types, have awakened a great interest in these two specialised and isolated genera. When, in addition to this, we consider that the Psilotaceæ is the only group of Pteridophytes in which the gametophyte generation and embryo are not yet definitely known, our interest in these plants becomes twofold, and any new information throwing additional light on their life-histories will be welcomed.

Flight—defined as the ability to produce useful aerodynamic forces by flapping wings—is one of the most demanding adaptations in vertebrates. The mechanical problems of flight ensure considerable external morphological homogeneity and behavioural similarity in extant fliers. Observations of the vortex wakes and wingbeat geometry of modern birds and bats confirm that the two groups are mechanically very similar, despite differences in phylogeny, anatomy and physiology. With this background it is possible to attack two problems: the evolution of flight in vertebrates, and the flight performance of extinct animals such as pterosaurs and Archaeopteryx.

The origin of flight has been surrounded by considerable controversy, due in part to terminological inconsistencies, in part to phylogenetic uncertainty over the relationships of birds, bats and pterosaurs, in part to disagreement over the interpretation of the available fossil evidence, and in part to argument over the relative importance of morphological, mechanical and ecological specialisations. The mechanical changes needed in the course of the evolution of flight favour a gliding origin of tetrapod flight, and on mechanical and ecological grounds the alternative cursorial hypothesis may be discounted. This argument is particularly strong in bats, but has been thought to be weaker in birds owing to apparent inconsistencies with the fossil evidence. However, fossils of the Jurassic theropod dinosaur Archaeopteryx also support a gliding origin for flight, and suggest that this animal was adapted for flapping flight at moderately high speeds associated with gliding; it could fly less well at the slow speeds which would have been required for incipient flight in a running cursor, and at which the wingbeat is aerodynamically and kinematically considerably more complex. Slow flight in birds and bats is the more derived condition, and vertebrate flapping flight apparently evolved through a gliding stage.

The pterosaurs have become the subject of much controversy over the nature of their stance, the wing surface, and the degree of involvement of the leg in the wing membrane. Reconstruction of their wings indicates proficient flying animals, and comparison with birds suggests that most pterosaurs probably occupied marine or coastal/estuarine habitat.

The genus Cephalodiscus was instituted by M'Intosh for a species, C. dodecalophus, which had been obtained by the Challenger Expedition. After the publication of the full account of this species, by M'Intosh and Harmer (87) in the Challenger Report, succeeding papers for nearly twenty years were all based on the original Challenger material. The subject was in particular re-investigated by Masterman in a series of papers (971, 972, 98, 99, 03). The Siboga report, published by Hakmer (05) in 1905, added three Oriental species to the genus. Schepotieff (05, 07, 08) devoted several papers to a further description of the Challenger material; while, more recently (09), he has described an interesting new species, C. indicus, from Ceylon. In 1906 Ridewood (06) described C. gilchristi from South Africa; and in the following year he gave an account (071) of the two species which had been dredged by the Discovery Expedition; and (072) of the development of the plumes in four species of Cephalodiscus. One of the Discovery species, C. nigrescens, had been described two years earlier by Lankester (05), in a preliminary paper; and Ridewood (12) has recently brought forward evidence to show that this species had been dredged by the Erebus and Terror Expedition in 1841 or 1842. In 1907 Andersson (07) added no less than six species to the genus, in describing the results of the Swedish South Polar Expedition, though we give some evidence (pp. 559–563) to show that one of them, C. inæquatus, is synonymous with C. hodgsoni, which had been described by Ridewood (071) earlier in the same year, from the Discovery collection. The most recent addition to the list of species has been given by Gravier (12), who has published an account of C. anderssoni, a new species which was obtained by the second French Antarctic Expedition.

The Bail Hill Volcanic Group (Caradoc) represents the largest, single volcanic complex exposed within the Ordovician turbidite succession of the Northern Belt in the Southern Uplands of Scotland. The group comprises a heterogeneous sequence of submarine lavas, volcaniclastic and intrusive rocks (up to 2 km thick), and crops out in a small area (c. 4 km2) around Bail Hill, north of Sanquhar. The Cat Cleuch Formation (older) is dominated by a sequence of autobrecciated basaltic lavas which contain large, zoned diopsidic clinopyroxene. The overlying Peat Rig Formation comprises a more mixed sequence of plagioclase-amphibole-phyric lavas, volcaniclastic rocks and contemporaneous volcaniclastic sedimentary rocks. The Cat Cleuch and lower part of the Peat Rig formations are cut by a vent breccia, the Bught Craig vent breccia, which formed part of the feeder to the upper part of the Peat Rig Formation. The Bail Hill volcanic rocks are alkaline in character, ranging from alkali basalt to trachyandesite in composition, possessing trace element characteristics and enrichment patterns typical of oceanic within-plate basalts. The Bail Hill Volcanic Group, although geochemically distinct, forms part of a mixed assemblage of tholeiitic and alkaline withinplate lavas within the Southern Uplands which are of broadly similar age, some of which are intercalated within the greywacke sandstone sequence. This assemblage clearly indicates that a period of extension and within-plate volcanism occurred during the early stages of the development of the Southern Uplands sedimentary basin.

Comparative Anatomists have long been desirous to obtain detailed information on the Placentation of the Sloths. The only observations on this subject which appear to have been made up to this time have been recorded by Professor Rudolphi of Berlin, and Dr C. G. Carus of Dresden. Rudolphi in the course of some remarks on the structure of the umbilical cord in Bradypus tridactylus incidentally mentions that the placenta was cotyledonary as in the Ruminants. Carus figures the placenta and an almost mature fœtus of a B. tridactylus which came into his possession in 1830. He gives no description, however, of the specimen, but contents himself with a brief explanation of his engraved figures; in the course of which he says, that the specimen seemed to him important on account of the length of the umbilical cord, and the form of the cotyledons, which did not project, as is usual, outwards, but towards the inner face of the ovum, a peculiarity which had not yet been observed and described.

Arthropods were the first known animals to colonise land habitats, with myriapods and arachnids having done so at least by the Silurian. Much later, several lineages of Pancrustacea (hexapods and the paraphyletic crustaceans) also ventured onto land; the hexapods by the Early Devonian, and later at least four other groups of crustaceans, namely isopods, amphipods, ostracods and decapods, most of which generally colonised the continental water bodies. All faced a series of challenges (in particular: gas exchange; desiccation; reproduction; osmoregulation; and exposure to ultraviolet radiation), resulting in many morphological, physiological and ecological adaptations. Nonetheless, whether they reached land via saltwater or freshwater remains poorly documented, mainly because relevant localities are few. The Famennian (Late Devonian) Strud locality in Belgium provided an exceptional source of information on early aquatic continental ecosystems and their plant, vertebrate and arthropod colonisers at a crucial step in the terrestrialisation process. Here, we review and update its crustacean fauna, which inhabited floodplain and temporary pool waters. New anatomical details of the notostracan Strudops goldenbergi Lagebro et al., 2015, as well as a new genus and species of spinicaudatan, are described. We also discuss the ecology of this unique, early continental ecosystem and the insights it gives into the terrestrialisation process.