During a visit to the Isle of Bute in the summer of 1920 I took the opportunity of collecting a number of the smaller Oligochæta on the shore at Ascog, and in a pond on the hill just above the village. An account of this collection is given in the present paper; I have also added notes on a few species I have met with since then near Edinburgh. For laboratory accommodation at Ascog I have to thank Prof. L. P. W. Renouf, at that time Superintendent of the Biological Station, who very kindly placed the resources of the institution at my disposal.

Selaginella grandis, a native of Borneo but now widely grown in Botanic Gardens, was first described by Moore (12). It presents a number of points of considerable morphological interest which have been briefly described by various writers including Goebel (6, 7, 8), Harvey-Gibson (9, 10), Seward (13), Uphof (16), and Worsdell (18). So far as I am aware, however, no full account of the morphology of this species has hitherto been published. My attention was drawn by Professor Drummond to certain abnormal developments exhibited by the plants growing in the Botanic Garden of Glasgow, and, in an endeavour to interpret these, I was led to investigate the normal morphology of this species. Accordingly, in this memoir, the normal morphology will first be described, after which the variations from the normal and certain experimental results will be considered.

The glaciation of East Lothian has already been dealt with separately by Professor John Young, who, when attached to the Geological Survey, treated this subject in the memoir of the district published in 1866. His account of the phenomena, striæ, boulder clay, dry valleys, etc., is concise and clear, but he does not enter deeply into a discussion of causes. A guarded reference to submersion to account for the presence of an erratic boulder of carboniferous sandstone at a height of 1500 feet above sea-level shows in fact that he had not arrived at a full conception of the possibilities involved in glaciation by land ice. He was, however, quite definite in ascribing many important erosion effects in the district to the work of an “ice-stream.” In this as in most other points he had been forstalled by Sir Archibald Geikie, who had already described the immediately adjoining area to the south.

Sulphur isotopic data are presented for the four horizons of stratabound mineralisation in the Argyll Group Dalradian (Vendian) of the Central Highlands of Scotland. The styles of mineralisation reflect the stratigraphic and tectonic evolution of the Dalradian basin. The SEDEX-type Ba + (Zn + Pb) Loch Lyon Horizon has δ34S values for pyrite of +17% and for baryte of +27%. The baryte sulphur source was Dalradian sea-water although the values were modified by isotopic exchange with an H2S-rich metamorphic fluid derived from the surrounding graphitic schists. The sulphur source for sulphide in the horizon was probably the underlying strata; sulphide values were only slightly affected by metamorphism. Sulphides in the Pyrite Horizon are isotopically indistinguishable from those in the remainder of the volcanogenic Ben Lawers Schist Formation (0 ± 4%); these values suggest that, at least in the Tyndrum area, sulphides in the Pyrite Horizon are of igneous origin. VMS-type Cu + Zn + Pb mineralisation in the Ben Challum Quartzite Formation has a narrow range of values around + ll%. The likely source of this sulphide sulphur is reduced sea-water sulphate, the isotopic values remaining consistent owing to the buffering effect of anhydrite in the underlying calcium-rich rocks.

Distribution patterns of eye-lenses are compared from forty-two preserved visual surfaces of the new phacopine trilobite Phacops (Phacops) tafilaltensis n. sp. from the Late Devonian of Tafilalt, Morocco. In this species, variation in the lens pattern is most common on the ventral and posterior parts of the visual surface. Post-larval specimens typically have seventeen or eighteen files of lenses, but the number present is not correlated with specimen size. Several individuals display seventeen files in one eye and eighteen in the other. The smaller number of files in one eye may reflect incomplete development of that visual surface. The length of the active section of the generative zone and its pattern of growth control the number of dorso-ventral files of lenses and their relative height. Cases of asymmetry in lens distribution are observed in six individuals. The capacity of these organisms to correct both environmental or genetic stresses appears to be weak for this character. The existence of individuals with eyes exhibiting a different number of files confirms that file number is the result of a genetically controlled developmental program. In Phacops (Phacops) tafilaltensis n. sp., the lenses are normally arranged in a regular pattern of hexagonal close packing, their size varies within the visual surface of individual specimens and their number increases during ontogeny. Variation in the timing of lens emplacement accounts for the observed irregularities in lens distribution, i.e. in ventral and posterior parts of the visual surface. Characteristic patterns of the lens arrangement on the visual surface relate to systematic categories and probably reflect evolutionary relationships.

In the first part of this memoir I described the structure of the corpuscles at a stage of larval development when the red cells were actively dividing and the blood contained several varieties of white cells. During the course of these more strictly cytological observations, it was impressed upon me that the great size of the elements and their very marked histological characters, combined with the simple character of the organisation of the animal, made Lepidosiren a very favourable case for the study of the first principles of Hæmatogenesis. I was specially interested in what may be termed a middle phase in the history of the blood. I refer to a period after the primitive corpuscles have acquired haemoglobin and there are leucocytes present, but before the blood-forming organs are unfolded. This stage lasts a relatively long time in Lepidosiren up to the differentiation of the spleen, as the liver takes no part in blood-formation at any period.

Jan Mayen, so far as at present known, is entirely volcanic in origin. The rocks, therefore, are conveniently grouped with the Tertiary and later volcanics of the Faroes, Iceland, and Scoresby Sound in East Greenland. It should be noted, however, that these three localities are linked together by the Faroe-Iceland Ridge, the water everywhere being shallower than 500 fathoms. Jan Mayen, on the other hand, though lying at the same distance from Iceland as the Faroes, is not on the Ridge, and is separated by depths of over 1000 fathoms. Its position is somewhat to the west of the centre of the Norwegian Sea, and at no great distance from depths exceeding 2000 fathoms.

The shallow synclinal fold termed the Dalmahoy syncline is situated between the north-western flank of the Pentland Hills and the Murieston fault, the most southerly of the five important easterly and north-easterly dislocations which traverse the oil-shale field of West Lothian. The core of the syncline is occupied by rocks belonging to the lower division of the Oil-Shale Group of the Lower Carboniferous. Intervening between these and the Cement-stone Group is a volcanic zone, probably on the same horizon as the Arthur's Seat lavas, consisting mainly of mugearites and basalts which show their greatest development in the Corston Hill district. Along the whole of the southern limb of the syncline is an extensive spread of Upper Old Red Sandstone, but this formation is almost entirely cut out in the northern limb by the Murieston fault, appearing only in the core of a small anticline near Selms.

Chondrichthyan teeth from a new locality in the Scottish Borders supply additional evidence of Early Carboniferous chondrichthyans in the UK. The interbedded dolostones and siltstones of the Ballagan Formation exposed along Whitrope Burn are interpreted as representing a restricted lagoonal environment that received significant amounts of land-derived sediment. This site is palynologically dated to the latest Tournaisian–early Viséan. The diverse dental fauna documented here is dominated by large crushing holocephalan toothplates, with very few, small non-crushing chondrichthyan teeth. Two new taxa are named and described. Our samples are consistent with worldwide evidence that chondrichthyan crushing faunas are common following the Hangenberg extinction event. The lagoonal habitat represented by Whitrope Burn may represent a temporary refugium that was host to a near-relict fauna dominated by large holocephalan chondrichthyans with crushing dentitions. Many of these had already become scarce in other localities by the Viséan and become extinct later in the Carboniferous. This fauna provides evidence of early endemism or niche separation within European chondrichthyan faunas at this time. This evidence points to a complex picture in which the diversity of durophagous chondrichthyans is controlled by narrow spatial shifts in niche availability over time.

Several specimens of myriapodous arthropods have been discovered at the early Carboniferous East Kirkton site near Bathgate, West Lothian, Scotland. None is particularly well preserved, but they are the earliest known Carboniferous myriapods, filling the time gap between the Old Red Sandstone of the early Devonian and the abundant myriapod faunas of the late Carboniferous (Pennsylvanian). One of the specimens, a milliped, provides the earliest evidence for both ozopores (repugnatorial gland openings) and spiracles. A second milliped specimen has some characteristics of the living Order Glomeridesmida, and hence of Enghoff's (1990) ‘ground plan’ of chilognathan millipeds. Aspects of these forms and a third suggest a novel early Carboniferous fauna clearly different from both earlier and later ones. The taxon name ‘Myriapoda’ should be abandoned, since it covers a group now recognised as paraphyletic. ‘Archipolypoda’ is probably synonymous with Order Euphoberiida, Class Diplopoda.

Psalixochlaena berwickense sp. nov. is described from specimens found in the Cementstone Group of Berwickshire. The incomplete fossils consist of short cylindrical stems, 0·7–1·5 mm diameter, and probably represent portions of one or more branching rhizomes. Attached petioles have not been seen but one detached fragment shows a resemblance in structure to the petioles of P. cylindrica (Williamson) Holden. Branching of the stem is by trifurcate laterals and this distinguishes it from P. cylindrica but bears a superficial resemblance to Rowleya trifurcata Long.

Historic type and referred material of the aetosaurian taxa Typothorax coccinarum, Episcoposaurus horridus and Episcoposaurus haplocerus are redescribed and the non-aetosaurian material identified and removed, a task previously considered “hopeless”. Reexamination of the original material reveals that the holotypes of E. haplocerus and probably T. coccinarum are not diagnosable at the species level and therefore are nomena dubia. The next available names for material referred to these taxa are Desmatosuchus spurensis and E. horridus respectively, although it may be more desirable for reasons of taxonomic stability to attempt to petition for a neotype in the latter case. The redescription of historical specimens is necessary to determine their nomenclatural validity. The use of referred specimens as proxy “type” specimens is problematic, as these referrals were originally made not on the basis of apomorphies, but rather on biostratigraphic and/or geographical assumptions which are inherently circular and cannot be unambiguously supported.

The protaspid ontogeny of Bolaspidella housensis (Walcott, 1886) is re-described. This species is known from the Marjum Formation (Lower Marjuman Stage) of western Utah, USA. Three protaspid stages are recognised, with the instars discriminated most readily by different spacing between the postero-lateral ends of the fixigena. Protaspides of B. housensis are shown to be similar to those of Glaphyraspis parva, from several Upper Cambrian localities in the USA, and Ptychopariide sp. E from the Upper Cambrian of the Wasatch Mountains in Utah, USA.

A review of the faunistic composition of the coleopterous taphocenoses from Bembridge Marls is given. Only two families (Cupedidae and Carabidae) have been recorded from this site before. A total of 31 families have been revealed and determined in the course of the recent study, and 42 species have been described: Agabus latissimus Ponomarenko, sp. nov. and Ilybius gratshevi Ponomarenko, sp. nov. from Dytiscidae; Neothanes europaeus Ponomarenko, sp. nov. from Carabidae; Spercheus punctatus Ponomarenko, sp. nov., Spercheus wightensis Ponomarenko, sp. nov. from Spercheidae, Hydrochara woodwardi Ponomarenko & Soriano, sp. nov. and Berosus barclayi Ponomarenko & Soriano, sp. nov. from Hydrophilidae; Ochthebius rossi Kirejtshuk, sp. nov., Eolimnebius fossilis Kirejtshuk, sp. nov., Hydraenites gracilimmus Kirejtshuk, sp. nov., Metacoxites ventritalis Kirejtshuk, sp. nov., Davidraenites gratshevi Kirejtshuk, sp. nov., D. interruptus Kirejtshuk, sp. nov. and D. spurcus Kirejtshuk, sp. nov. from Hydraenidae; Aphodius vectis Krell, sp. nov. and Pentodon dorcus Krell, sp. nov. from Scarabaeidae; Scirtes calcariferens Kirejtshuk & Ponomarenko, sp. nov., Scirtes khnzoryani Kirejtshuk & Ponomarenko, sp. nov., Scirtes metepisternalis Kirejtshuk & Ponomarenko, sp. nov., Scirtes wightensis Kirejtshuk & Ponomarenko, sp. nov., Contacyphon insularis Kirejtshuk & Ponomarenko, sp. nov., Contacyphon involutus Kirejtshuk & Ponomarenko, sp. nov. and Contacyphon kozlovi Kirejtshuk & Ponomarenko, sp. nov. from Scirtidae; Eucinetes nikolaevae Kirejtshuk & Ponomarenko, sp. nov. from Eucinetidae; Macropunctum rossi Alexeev, sp. nov. from Elateridae; Byrrhites bembridgensis Kirejtshuk, sp. nov. from Byrrhidae; Paralichas striatopunctatus Kirejtshuk, sp. nov. from Ptilodactylidae; Trixagus barclayi Kirejtshuk, sp. nov. from Throscidae; Themus (?Telephorops) polyaki Kirejtshuk, sp. nov. from Cantharidae; Attalus flexus Kirejtshuk, sp. nov. from Malachiidae; Epuraea (Epuraea) kozlovi Kirejtshuk & Kurochkin, sp. nov., Phenolia (Lasiodites) vanescens Kirejtshuk & Kurochkin, sp. nov., Prometopia europaea Kirejtshuk & Kurochkin, sp. nov., Cyllodes argutus Kirejtshuk & Kurochkin, sp. nov. and Coxollodes palaeogenicus Kirejtshuk & Kurochkin, sp. nov. from Nitidulidae; Telmatophilus britannicus Kirejtshuk & Kurochkin, sp. nov. from Cryptophagidae; Corticariites kozlovi Kirejtshuk, sp. nov. from Latridiidae; Orthoperites antiquus Kirejtshuk & Kurochkin, sp. nov. from Corylophidae; Octotemnites sepultus Kirejtshuk, sp. nov. from Ciidae; Cyclodinus efficax Kirejtshuk, sp. nov. from Anthicidae; and Plateumaris robustus Kurochkin & Kirejtshuk, sp. nov., Plateumaris rubiconis Kurochkin & Kirejtshuk, sp. nov. and Plateumaris wightensis Kurochkin & Kirejtshuk, sp. nov. from Chrysomelidae. Byrrhites Kirejtshuk, gen. nov., Corticariites Kirejtshuk, gen. nov., Davidraenites Kirejtshuk, gen. nov., Eolimnebius Kirejtshuk, gen. nov., Hydraenites Kirejtshuk, gen. nov., Metacoxites Kirejtshuk, gen. nov., Octotemnites Kirejtshuk, gen. nov. and Orthoperites Kirejtshuk & Kurochkin, gen. nov. are proposed as taxa, partly as formal ones with generic rank and include species described herein. For Plateumaris rubiconis sp. nov., a new subgenus Necrodexis Kurochkin & Kirejtshuk, subgen. nov. is proposed. A brief review of the published fossil records for the groups considered in the paper is made. The probable ecological circumstances of the lives of the groups and species considered are discussed in the paper, and comparison with other Palaeogene sites and some conclusions on probable climatic circumstances have been elaborated. The taxonomic interpretation of three fossil species from the Caenozoic is reconsidered. It is shown that the genus Miocyphon Wickham, 1914 can be scarcely regarded as a close relative of representatives of either Dascillidae or Scirtidae. ‘Phenolia' incapax Scudder, 1890 and Lithomacratria Wickham, 1914 are regarded here without family attribution, the first as a member of Cucujiformia (i.e., out of Nitidulidae) and the latter as a member of the superfamily Tenebrionoidea (i.e., out of both Anthicidae and Pyrochroidae).

Immediately W of the islands of Uist in the Outer Hebrides is a wide, low-gradient submarine shelf on which glacifluvial deposits of Devensian age and calcareous sand accumulated. Following moulding by Devensian ice, the Lateglacial landscape of the littoral zone of the Uists became a series of low-lying bedrock ridges and basins. The analysis of sub-tidal organic deposits has shown that in the early Holocene this landscape supported water bodies, marshes and a vegetation mosaic of Betula-Corylus woodland and Calluna vulgaris-herbaceous taxa open ground. The submergence of this littoral area during the Holocene Marine Transgression, together with wave action typical of the position on the Atlantic margin, led to the transfer onshore of submarine shelf deposits, so creating machair (sand plain) landscapes. This brought about vegetational changes, eventually creating calcareous grasslands. The timing of these events was asynchronous, being location- and site-specific due to variations in the configuration of the littoral zone. Although the date of the initial transfer of sand is unknown, evidence from the sub-tidal deposits indicates that a major incursion of sand, in North Uist, occurred c. 7600 BP (8450–8340 cal BP). The same source also suggests that a further major sand movement took place during the period 5800–4200 cal BP, a period of widespread sand drift in NW Europe. The analyses of the sub-tidal deposits have also reinforced the current theory of machair evolution.

In Strathaird, Tertiary lavas occupy an area of about 7 square miles and are up to 1000 ft. thick. Most of the sequence consists of alkaline olivine basalts but there is also a flow of trachybasalt and a thin group of picritic lavas. Pyroclastic rocks are rare.

The area lies along the south-eastern margin of the Cuillin gabbro and thermal metamorphism is evident to a varying degree over the whole of the lava outcrop. In the immediate vicinity of the gabbro the lavas have been recrystallized to pyroxene-bearing hornfelses, and these rocks are followed outwards by a broader zone characterized by the presence of actinolite, chlorite, albite and epidote. In the outermost of the three zones, which extends for at least 3 miles from the gabbro, thermal effects are limited to the local growth of chlorite, albite and epidote. When compared with Turner's (1958) scheme of metamorphic facies the inner zone is equivalent to the pyroxene hornfels and sanidinite facies whereas the two outer zones form subdivisions of the albite-epidote hornfels facies. The hornblende hornfels facies appears to be only poorly represented by a few hornfelses found on the outer boundary of the inner zone.

The metamorphism was not progressive since the mineral assemblages of each zone developed independently from unmodified lavas. There is evidence that a small amount of silica was added to some of the inner zone lavas during metamorphism.

Eight new chemical analyses of metamorphosed basalts are presented, together with one new analysis of a metamorphosed bole.

The modes of life and environments of the extant agnathans (cyclostomes) are discussed in relation to their adaptations to temperature, light, oxygen and salinity. As their antitropical distribution indicates, both hagfishes and lampreys are cold water groups. Since hagfishes live in deeper waters than lampreys, they are not exposed to the marked seasonal changes in temperature and light which influence major events in the lamprey life cycle. Both groups tend to be nocturnally active, either burrowing during daylight as in the case of larval lampreys (ammocoetes) and most hagfishes, or showing cryptic behaviour as in the case of adult lampreys. Olfaction plays a major part in the location of prey, presumably aided in adult lampreys by their eyes and sensitive electrosensory system. Rates of standard oxygen consumption, ventilatory frequency and heart rate of adult lampreys increase at night. Standard oxygen consumption is relatively low in ammocoetes (as it also is in hagfishes) but increases markedly during metamorphosis into the adult lamprey. Ammocoetes and hagfishes, and to a lesser extent adult lampreys, are resistant to reduced environmental oxygen tensions. Differences in the oxygen dissociation curves of ammocoetes, adult lampreys and hagfishes can be related to differences in the characteristics of their monomeric haemoglobins and their environments and modes of life. The extraordinary tolerance of the hagfish heart to hypoxia is a reflection of a robust capacity for glycolysis, an LDH isozyme geared towards anaerobic functioning and a low work output. The hagfishes, which are restricted to marine waters, are osmoconformers. The osmolality of their blood, which is almost wholly attributable to inorganic ions, is virtually identical to that of full strength sea water (c. 1000 mOsmkg−1). By contrast, the osmolality of the blood of larval and adult lampreys when in fresh water is only 205-260 mOsm kg−1, i.e. about one quarter to one fifth of those of hagfish, and these rise only to 240-270 mOsm kg−1 in the adults of anadromous lampreys in sea water. The regulation of ions by adult lampreys is achieved by mechanisms similar to those adopted by teleosts. The implications of the contrasting ionic and osmotic physiology of the two living groups of agnathans are discussed in relation to their possible environmental history and against the background of their Carboniferous fossil representatives.

The development of the Midland Valley of Scotland from Silurian times is re-examined. Earlier (Cambro-Ordovician) terrane accretion of the Midland Valley Terrane to the Laurentian continent by sinistral strike-slip continued to control basin development, sedimentary facies distribution and deformation from Llandovery through to at least early Devonian times. A widespread Mid- to Late-Wenlock strike-slip event has been recognised. This event is variable in its effect, but may indicate a direct link between the Midland Valley, Southern Uplands and Grampian terranes, suggesting that the terranes were juxtaposed by Mid-Wenlock times. In the Midland Valley this event was followed by a renewed phase of basin development with the deposition of ?Pridoli-Lower Devonian clastic sediments which was interrupted by the Lower Devonian volcanic event. There was a shift northwards in the focus of Lower Devonian basin development which was accompanied by a diachronous deformation event across the Midland Valley which resulted in inversion/uplift from early to middle Devonian times. This phase of deformation, uplift and erosion may be related to end-Caledonian transpression.