The Rhizodontida (Pisces: Sarcopterygii) is a clade of predatory fishes from the Upper Devonian (Aztecia; ?Givetian of Antarctica) through to the Upper Carboniferous (Strepsodus; Moscovian of northern Europe and North America). They form the most basal plesion within the tetrapod stem-lineage. The mandibles were dominated by large symphysial tusks on the dentary. Not much else is known of the mandibles in primitive rhizodontids. However, later forms show several derived characters: the mandible is very deep dorsoventrally and narrow linguolabially; the coronoid fangs bear only a single fang and no other dentition; the Meckelian element was unossified, leaving the adductor fossa unfloored by bone; the prearticular produced a large dorsal process lingual to the adductor fossa, presumably for muscle attachment. These and other characters are discussed in the context of the evolution of the tetrapod stem-group.

The mandible appears to have been split into two functional units, one comprising the firmly sutured prearticular, coronoids and dentary, the other comprising the firmly sutured infradentaries. The connection between the two units was weak, suggesting a longitudinal intramandibular hinge. The possibility that this acted as a ‘torsion grip’ during feeding is discussed.

The object of this paper is to discuss the recently discovered encystment of Tardigrada, as far as our imperfect knowledge permits; to compare the process with that observed in certain low groups of the Acarina, in which the Tardigrada are generally considered to have their nearest relatives; then to inquire whether these new facts throw any light on certain puzzling facts in the physiology of the Tardigrada and Acarina, such as the retrogression which produces the simplex forms of Tardigrada, and which is said to accompany each moult of the Acarina; and lastly, if they contribute anything towards settling definitely the systematic position of the Tardigrada.

In this paper some properties of the functions J[n](x, λ), P[n](x, λ), Q[n](x, λ) will be investigated. These functions are generalised forms of Bessel's and Legendre's Functions.

The Vila Pouca de Aguiar granite pluton, emplaced during the latest event of the Variscan orogeny of northern Portugal, is here subjected to a detailed study that combines magnetic fabric measurements and gravity modelling of its shape at depth. This laccolith, less than 1 km in thickness over ≈60% of its outcrop area, appears to be fed from its northern area, through narrow conduits, up to 5 km deep, belonging to a set of Y-shaped valleys that almost perfectly correspond to the local Régua–Verin fault-system identified in the geological maps. A normal petrographical zonation, already identified geologically, appears to be rather progressive, although a gradient in magnetic suceptibility magnitude in-between the two main magma types is evidenced. It is suggested that the first to be emplaced and the least evolved granite type (Vila Pouca de Aguiar Granite) upwelled from the local, NE-trending fault-zone, acting as a dyke, and formed a thin sill where NE-directed magma flow was dominant, at least close to the floor. The more evolved granite type (Pedras Salgadas Granite), located just above the main feeder zone, and deeply rooted at the intersection beween underlying faults, is at the centre of a remarkably regular concentric distribution of the foliation trajectories. They may reflect the late doming of the laccolith's northern part, coeval with a slight E-W extension of the inflating magma reservoir, as marked by the E-W-trending lineations. Along with ubiquitous magmatic to near-magmatic microstructures and particularly low anisotropy magnitudes, such patterns can be entirely explained by magma movement within its inflating reservoir. This composite laccolith, during emplacement of which no interference with the regional strain pattern can be recorded, is therefore considered as typical of post-tectonic emplacement.

In the seaward direction in an estuary there are usually the following main gradients:—

(a) Increase in osmotic pressure (total salt content, especially chlorides).

(b) Increase in calcium and magnesium content.

(c) Increase in alkalinity.

(d) Increase in winter and decrease in summer temperature.

(e) Increase in light penetration.

There are other gradients of less importance. The first three are dependent on salinity. Thus, from the ecological standpoint, the three important physical observations relative to the study of estuarine life are the salinity, temperature, and light (silt content) gradients.

Ecological studies are directed towards the elucidation of two types of problems:

(i) Characteristics of the physical environment relevant to the distribution of specific forms of life.

(ii) The growth of mixed populations and their interrelations in a homogeneous environment or in a physical gradient.

The present study concerns itself especially with the former, and to a less extent with the latter.

Several authors have proposed that granitic melt accumulation and transport from the source region occurs in networks of connected melt-filled veins and dykes. These models envisage the smallest leucosomes as ‘rivulets’ that connect to feed larger dykes that form the ‘rivers’ through which magma ascends through the sub-solidus crust. This paper critically reviews this ‘rivulets-feeding-rivers’ model. It is argued that such melt-filled networks are unlikely to develop in nature, because melt flows and accumulates well before a fully connected network can be established. In the alternative stepwise accumulation model, flow and accumulation is transient in both space and time. Observations on migmatites at Port Navalo, France, that were used to support the existence of melt-filled networks are discussed and reinterpreted. In this interpretation, the structures in these migmatites are consistent with the collapse and draining of individual melt batches, supporting the stepwise accumulation model.

My first knowledge of Stenomyelon Tuedianum was derived from a microscopical preparation in the collection of the late Mr C. W. Peach, A.L.S., which, through the kindness of his son, Dr B. N. Peach, F.R.S., subsequently came into my possession. The specimen was labelled as having been found “near Berwick.”

Flandrian (Holocene) relative sea level changes in the lower Ythan valley, NE Scotland, U.K., are inferred from detailed stratigraphical evidence including microfossil analysis and radiocarbon assay. The principal event recorded is the Main Postglacial Transgression, which was under way in the area by c. 8300 and had culminated before c. 4000 radiocarbon years BP. It is concluded that the rise in relative sea levels during the transgression in the area exceeded 12 m; that the mean rate of rise there was 8·05 mm a−1 between c. 8300 and c. 7100 radiocarbon years BP, or 7·09 mm a−1 based upon calibrated dates for the same period, before declining markedly to 1·75 mm a−1 (radiocarbon) or 1·86 mm a−1 (calibrated) to the culmination of the event. By comparison with other sites, the culmination appears to have been time-transgressive in eastern Scotland. Deposits of the Second Storegga Slide tsunami, which occurred during the Main Postglacial Transgression, are present in the Ythan valley, where the sediment run-up of the event at the sites studied is estimated to have been within the range 2·99–5·19 m.

In a preceding paper of this series it was pointed out that the smooth branched axes, which are so common in the Middle Old Red Sandstone of Scotland, cannot be assumed to belong to one kind of plant. They were therefore for convenience referred to as Hostimella sp. It was further shown that three distinct types of sporangia were associated with axes of this general type and, on the characters afforded by the reproductive organs, three species were distinguished. These were provisionally retained under the generic name Hostimella, as H. pinnata, H. globosa, and H. racemosa. In the same paper it was mentioned that the linear bodies borne on the peculiar fossil known as Ptilophyton Thomsoni, Dawson, were almost certainly sporangia. This afforded another reproductive structure borne on a vegetative region, which, if found separately, could only be placed in Hostimella sp. Since, as had been pointed out by Kidston, the generic name Ptilophyton is inadmissible for this fossil, it was placed in the purely provisional genus Hostimella as H. Thomsoni. In the present paper the nature of this interesting member of the Scottish Middle Old Red Sandstone Flora will be more fully considered.

The investigations recorded in this communication were begun some years ago, and arose chiefly as the result of two papers published on the Geology of the Forest of Wyre by Mr T. C. Cantrill, B.Sc.

In the latter paper Mr Cantrill, after carefully summarising all the available data respecting the age of the so-called “Permian” of the Forest of Wyre (= Enville), arrives at the following conclusions:—

I. That these “Permian” rocks are of the same age as those at Hamstead in South Staffordshire.

II. That the Hamstead red rocks were shown by their flora to be Upper Coal Measures.

Newly discovered crustaceans from the Granton ‘shrimp-bed’ (Dinantian, Lower Oil Shale Group) are described: Bairdops elegans, Minicaris sp., Palaemysis, Tealliocaris cf. woodwardi, Pseudogalathea ornatissima, Anthracocaris scotica, Paraparchites cf. okeni, Beyrichiopsis plicata, and Eocypridina cf. aciculata, and new observations on Waterstonella grantonensis are reported. Tealliocaris woodwardi alone is recorded from bed o, a level ca 1 m below the ‘shrimp-bed’. The Granton ‘shrimp-bed’ biota is reviewed—the geological and lithological context of the deposit, the distribution and taphonomy of the biota, its life environment, palaeoecology, the likely causes of mortality, and comparisons are made with contemporaneous shrimp biotas. The nature of this unusual Konservat-Lagerstätte reflects conditions in the sheltered, periodically emergent lagoon which it represents.

The presence of a fungus on grains of perennial rye-grass which failed to germinate was recorded in New Zealand by Hyde in 1932. In 1938 the same fungus was associated by Hyde with exceptionally low germination in Italian rye-grass and, later that year (Hyde, 1938 a), the poor germinating capacity was ascribed to infection by Pullularia. Seed of the Scottish harvest of 1938 showed the signs of infection by Pullularia described in Hyde's papers (Noble, 1939), and cultures obtained from mycelium within infected seed, sterilised on the surface, were identified as Pullularia pullulans (De Bary) Berk.

A study of type and newly collected material of the Silurian ostracod Richteria migrans (Barrande, 1872) demonstrates that it had wide distribution, occurring in at least the Czech Republic, France, Sardinia, Wales, central Asia and probably Poland. R. migrans has biostratigraphic value, as an indicator for the mid to late part of the Ludlow Series. It was almost certainly pelagic, living predominantly in probable shelf topographic lows to marginal/off-shelf environments, characteristically with cephalopod-graptolite-bivalve-dominant associates. It had at least five to six growth stages, exhibits polymorphic variation, and its morphology provides evidence to endorse the notion that ‘entomozoaceans’ are myodocopes.

The existence of a series of trap dykes cutting the Old Red Sandstone strata of the Orkneys has been noted by most of the geologists who have examined the islands. In his description of the Mainland or Pomona, Professor Jameson states (I., p. 233, vol i.) that “at Yesknaby is the only basaltic rock which I observed in the whole island. It forms veins which traverse the common argillaceous sandstone. The crystals of hornblende, which are contained in it, are larger than usual in such rocks, being more than an inch long and half an inch broad. I sometimes observed small cavities filled with bitumen.” Sir Archibald Geikie, in his account of the Old Red Sandstone of Orkney, remarks (II., p. 408): “Here and there a few basalt dykes—far outlying portions, no doubt, of the great Tertiary series of the West of Scotland—cut through the flagstones with a prevalent direction towards west or north-west.” Messrs Peach and Horne, in their paper on The Old Red Sandstone of Orkney (III., p. 14), describe them in the following terms: “Several dykes of basalt were observed among the islands. They are most numerous and conspicuous on the west coast of the Mainland from Breckness to Skaill, but as they have been so often described, it is unnecessary to refer to them in detail. They have the same lithological characters, and behave in exactly the same manner as the dykes in other parts of Scotland, which have been regarded as the product of volcanic energy in Miocene times. A noticeable feature about the Orcadian representatives is, that they are usually divided up the centre of the dyke by a line of vesicles. This is not an uncommon feature elsewhere.” In the chapter on the Geology of Orkney in Tudor's The Orkneys and Shetland, by the same authors, the dykes are referred to in similar terms (IV., p. 191). A somewhat more minute examination of these dykes was made by Professor M. Foster Heddle. He notes the presence of augite, olivine, and hornblende in certain dykes near Skaill (V., p. 118), and gives a map of the dyke which cuts the west end of the granite outcrop at Inganess (V., pl. viii.). He figures also a crystal of augite of simple form which he found in a dyke on Scabra Head, Rousay (V., p. 128).

The problem of the origin of dinosaurs has historically had three dimensions. The first is the question of whether Dinosauria is monophyletic, and of its relationships to other archosaurs. This question was plagued from the beginning by a lack of relevant fossils, an historical burden of confusing taxonomic terms and a rudimentary approach to devising phylogenies. The second dimension concerns the functional and ecological adaptations that differentiated dinosaurs from other archosaurs, a question also marred by lack of phylogenetic clarity and testable biomechanical hypotheses. The third dimension comprises the stratigraphic timing of the origin of dinosaurian groups with respect to each other and to related groups, the question of its synchronicity among various geographic regions, and some of the associated paleoenvironmental circumstances. None of these dimensions alone answers the question of dinosaur origins, and they sometimes provide conflicting implications. Since Dinosauria was named, one or another set of questions has historically dominated academic discussion and research. Paradigms have shifted substantially in recent decades, and current evidence suggests that we are due for more such shifts. I suggest two changes in thinking about the beginning of the “Age of Dinosaurs”: first, the event that we call the (phylogenetic) origin of dinosaurs was trivial compared to the origin of Ornithodira; and second, the “Age of Dinosaurs” proper did not begin until the Jurassic. Re-framing our thinking on these issues will improve our understanding of clade dynamics, timing of macroevolutionary events, and the effects of Triassic climate change on terrestrial vertebrates.

In the Southern Uplands of Scotland, the youngest greywackes along the SE margin of the Northern Belt are shown to be of Ashgill age. Mudstones interbedded with the dominantly quartzose greywackes of the Shinnel Formation have yielded Dicellograptus anceps, indicating the anceps Biozone. In addition, the newly-defined mafic-rich Glenlee Formation, lying to the SE of the Shinnel Formation in the New Galloway-Moniaive area, has yielded fossils of the pacificus Subzone, the upper subzone of the anceps Biozone. Since the oldest greywackes of the Central Belt, separated from the Northern Belt by the Orlock Bridge Fault, are now confirmed as of basal Silurian acuminatus Biozone age, the stratigraphical break across the Orlock Bridge Fault is greatly reduced, lending support to the ‘single terrane’ model for the Southern Uplands.

Living Crustacea possess many types of sensory receptors that detect environmental signals. These structures allow the speculation that similar organs existed in fossil arthropods and were involved in similar ways in the fossil forms when they were extant.

Posture, for example, is difficult to reconstruct in fossils without the understanding that internal proprioceptors monitoring position and movement are crucial in determining the placement of limbs, and the position of the abdomen and other jointed portions of the body. These receptors are associated also with autotomy reflexes through soft cuticle detectors that respond to strain not associated with joints.

Many receptors are placed on the outer surface of the animal, the eyes being the most obvious. The eyes receive no attention in this paper, but descriptions are given of a number of different types of setae, serving both mechanical and chemical sensors. The possession of a pore at the apex (or sub-apex) of a seta or setule probably indicates a chemoreceptor function, but its absence does not necessarily indicate a lack of such sensitivity. A range of forms is illustrated.

The dorsal organ is a recently discovered structure in decapod larvae. It is composed of a central single gland cell opening via an aperture in the midline just behind the rostrum. It is bounded by four depressions each containing a central ‘nipple’. These prove to be sensors, with ciliated endings (bifid) that end in a highly modified cuticle at the depression nipple. The function is unknown, but it is proposed that it represents an unusual chemoreceptor.

The present work deals with the structure of the cephalic part, traces of the digestive system and gills of Ostenocaris cypriformis (Thylacocephala). The structure of the cephalic part has provoked the most substantial controversy since it has been interpreted as being formed by a pair of enormous compound eyes or as a sac structure that we have called the cephalic sac. Particular attention has been devoted to the minute structure of the cephalic sac. Structures that we have previously termed ‘microsclerites’ can be readily observed, but are by no means easy to interpret.

In many specimens, the basal part of the cephalic area contains abundant traces of alimentary residues. The area thus appears to be part of the digestive system. Our observations do not enable us to give a definitive picture of the anatomical organisation of these animals but do lead to substantial corrections of previously proposed interpretations.

The first record of the tribe Paussini Latreille is reported based on a specimen from late Eocene Rovno amber. It is the first known close relative of the genus Eohomopterus (subtribe Carabidomemnina) in the Old World. The recent and Neogene distribution of Eohomopterus is Neotropical, with extant representatives in Ecuador, Brazil and the West Indies, and extinct species in Dominican and Mexican amber. The occurrence of the Neotropical Carabidomemnina in Rovno amber and the presence of the Oriental Protopaussini in Dominican amber are of significant interest as evidence of the probable transarctic migrations of their ant host in the early Eocene.