Morphological studies of the braincase and cranial endocast of fossil crocodylians, especially gavialids, are scarce. Here, we present a detailed description of the neuroanatomy of Gryposuchus neogaeus from the Miocene of Argentina, based on CT scans. The cranial endocast is sub-horizontal and the angle formed between the mid-brain and the hind-brain is poorly marked. When compared with Gavialis gangeticus, the mid-brain of G. neogaeus is relatively shorter, although the distribution of cranial nerves is similar. In the floor of the endocranial cavity, posterior to the dorsum sellae, there is a median foramen that leads into a canal that runs anteroventrally through the basisphenoid to penetrate the posterior wall of the pituitary fossa (open foramen for the basilar artery?). The same structure is present in G. gangeticus, but is absent in other living crocodylians, suggesting a potential synapomorphy of Gavialoidea. The pneumaticity of the skull roof and the lateral branches of the pharyngotympanic system in G. neogaeus are markedly reduced when compared with the extant species. Comparisons with the living Gavialis indicate that the pattern of braincase morphology of Gavialidae was present in the Miocene; however, the internal morphology, including brain shape, pneumaticity of the skull roof and basicranium, is different in the two species. This work is the first step to understand the variation of the neuroanatomy in this group of archosaurs and its palaeobiological implication.

One of the most outstanding apparent examples in N America of a forcibly emplaced pluton is the Papoose Flat Pluton of eastern California. Sideways expansion of this granitic pluton, during emplacement into a series of Cambrian shelf strata, has been regarded by early workers as resulting in the observed intense crystal plastic deformation of the pluton's mylonitic border facies and surrounding country rocks. This deformation is evidenced by up to 90% thinning of individual stratigraphic layers within the pluton's metamorphic aureole, although such intense penetrative deformation of the country rocks is not observed outside the aureole.

Previously published quartz c-axis fabrics associated with this deformation (and presented on projection planes oriented perpendicular to lineation) were interpreted as being symmetrical with respect to foliation and lineation, implying almost coaxial deformation histories. Such fabrics could be interpreted as indicating that the pluton evolved by “ballooning” as a result of new magma being intruded into its core during emplacement. However, a major problem with applying the strict ballooning model to the Papoose Flat Pluton is that while oblate strains would be expected to develop in association with a ballooning mechanism, the mylonitic rocks of this elongate WNW-ESE-trending pluton and its aureole are characterised by both a strongly developed foliation, which is concordant with the pluton's margin, and an intense, NW-SE trending, shallow plunging stretching lineation.

Previously published fabrics from the Papoose Flat Pluton and its metamorphic aureole have been rotated on to a projection plane oriented parallel to lineation and perpendicular to foliation. Examination of the fabrics in this projection plane has revealed that they are in fact dominantly asymmetric, and that a constant sense of asymmetry is detected across the pluton, suggesting a consistent (top-to-the-SE) shear-sense. This new interpretation is strongly supported by microstructural and petrofabric analysis of additional L-S tectonites collected, during recent fieldwork, from both the aureole and quartz veins within the pluton's gneissic border facies. Thus mylonite formation around the Papoose Flat Pluton could have involved large-scale consistently oriented translation and associated shearing, rather than passive “blister-like” coaxial deformation associated with pluton ballooning. It should be noted that mylonitic deformation is restricted to the western half of the pluton, features indicative of a more “permitted” emplacement mechanism being found in the eastern portion of the pluton.

The detected top-to-the-SE shear-sense could be interpreted as indicating that the granitic material forming the western part of the pluton was forcibly intruded in a northwestward direction from the pluton source as a nearly solidified wedge beneath a static cover of sedimentary rocks. Alternatively, the detected shear sense could also be interpreted as indicating SE-directed thrusting of the cover rocks over the underlying pluton, the western margin of the pluton suffering intense mylonitic deformation, while the eastern margin was located in a “stress-shadow” region. If this alternative interpretation is correct, then the deformation temperatures indicated by the pattern of quartz c-axis fabrics dictate that thrusting must either be synchronous with pluton emplacement, or at least have commenced during the early stages of pluton cooling.

The shell and gizzard plates of Philine aperta were first described in 1616 by Fabius Colonna. Linnæus (1767) included the animal in his genus Bulla, and named it Bulla aperta. In 1772 Ascanius made a new genus, Philine, with P. aperta as type.

Cuvier (1810) created the order Tectibranchiata, and in the “Règne Animal” (1817) grouped in this order Pleurobranchus, Aplysia, Dolabella, Notarchus, Bulla, and Philine.

Fischer (1887) divided the Tectibranchs into the Cephalaspidea, the Anaspidea, and the Notaspidea; the first with a cephalic disc, the last with a dorsal shield, and the Anaspidea with neither.

Xenacanthids were a very successful group of elasmobranchs that ranged from the Lower Carboniferous to the Upper Triassic. The history of discovery of the xenacanthids, which is closely connected with the history of coal prospecting in England, began with the finding of the type specimen of Xenacanthus laevissimus in the Westphalian B of the West Midlands. In this first review of British Carboniferous xenacanthids, the number of taxa, mainly erected during Victorian times, is reduced to 14 species distributed among six genera. Determinable remains are recorded from at least 96 localities in the British Isles. Unique characteristics of the Dinantian Diplodoselache suggest that the lineage to which this taxon belongs marks a dead end in xenacanthid evolution. This investigation also shows that the Pendleian Dicentrodus, formerly described as Cladodus, belongs to the xenacanthids. The occurrence of Orthacanthus cf. kounoviensis in the Pennines, also known from the German Saar-Nahe basin, the Saale depression and from Bohemia, indicates a faunal exchange between these intramontainous basins during the Carboniferous. The genus Triodus is identified from British deposits for the first time. A cladistic analysis of the xenacanthids suggests that they evolved from phoebodontid elasmobranchs. This analysis also confirms separation of the Middle Devonian Antarctilamna from a relationship with xenacanthid sharks.

Like many granites, the Late Cretaceous intrusives of the eastern Mojave Desert, California, have heretofore provided useful but poorly focused images of their source regions. New studies of lower crustal xenoliths and inherited accessory minerals are sharpening these images.

Xenoliths in Tertiary dykes in this region are the residues of an extensive partial melting event. Great diversity in their composition reflects initial heterogeneity (both igneous and sedimentary protoliths) and varying amounts of melt extraction (from <10% to >70%). Mineral assemblages and thermobarometry suggest that the melting event occurred at T ≥ 750°C at a depth of about 40 km. Present-day Sr, Nd, and Pb isotopic ratios indicate a Mojave Proterozoic heritage, but unrealistic model ages demonstrate the late Phanerozoic adjustment of parent/daughter ratios. A link between these xenoliths and the Late Cretaceous granites, though not fully documented, is probable; in any case, they provide invaluable clues concerning a crustal melting event, recording information about nature of source material (heterogeneous, supracrustal-rich), conditions of melting (moderately deep, moderately high T, accompanied by partial dehydration), and melt extraction (highly variable, locally extensive).

The Old Woman-Piute granites contain a large fraction of inherited zircon and monazite. A SHRIMP ion probe investigation shows that these zircons record a Proterozoic history similar to that which affected the Mojave region. Zonation patterns in zircons, and to a lesser extent monazites and xenotimes, document multiple phases of igneous, metamorphic, and sedimentary growth and degradation, commonly several in a single grain. Low Y in portions of the cores of inherited zircons and monazites and in monazites and outer portions of zircons from the xenoliths appear to indicate growth in equilibrium with abundant garnet.

Comprehensible explanations of the operation of earth climate systems should consist of descriptions of the operation of a few degrees of freedoms. Qualitative interpretations of results from large-scale numerical models generally follow this principle, but do not render formal definitions of the precise nature of such degrees of freedom.

At its simplest, ice-sheet kinematics requires knowledge of the evolving height and span. Rheology and surface mass-balance impose different requirements upon the co-evolution of these variables, meaning a two-degree of freedom model is over-prescribed. By means of a perturbation expansion about the analytic similarity solution for viscous spreading, eigenfunctions corresponding to degrees of freedom in the ice-sheet profile are obtained, and are used to decompose mass-balance distributions. Only a few eigenfunctions are needed to replicate numerical models, implying that ice-sheets in plane flow may operate with fewer than ten degrees of freedom.

Unstable evolution of ice-sheets can occur, when the operation of a very large number of degrees of freedom can be manifested. Previous work is reviewed and new results for the unstable transformation of valley glaciers into ice-sheets are presented. Phasing of initiation may be an unpredictable phenomenon.

The work recorded in this paper forms part of an investigation to determine how far the feeding mechanism of the simple Peracaridan Hemimysis lamornæ, which we have recently described (1927), represents a primitive Malacostracan type.

We have not been able to observe any living Syncarid, but have been fortunate in obtaining preserved specimens of the three genera Paranaspides, Anaspides, and Koonunga, together with a series of transverse sections of Anaspides. From a comparison of the structure and arrangement of their mouth parts and trunk limbs with those of Hemimysis and other Malacostraca which we have observed alive, we have been able to deduce their methods of feeding in considerable detail.

Excepting the few species noticed in the Report on the Ostracoda of the “Challenger” Expedition, scarcely anything, so far as I know, has been published respecting the Ostracoda of the South Sea Islands. Prof. G. M. Thomson has indeed published in the Transactions of the New Zealand Institute (1878), a paper on Crustacea, which includes a few marine and fresh-water Ostracoda of New Zealand; and the Rev. R. L. King, in the Proceedings of the Royal Society of Van Diemen's Land (1855), described numerous species of Entomostraca, amongst which were several fresh-water, but no marine, Ostracoda. Dr Baird also published a species of Cypridina from New Zealand. I have myself contributed to the Proceedings of the Zoological Society of London (1886) a paper on Entomostraca collected in South Australia, chiefly by Professor Ralph Tate of Adelaide, including a considerable number of fresh-water Ostracoda; and in a French publication (Les Fonds de la Mer), edited by the Marquis de Folin, there are likewise, by myself, descriptions of a few species taken at Nouméa, New Caledonia. There are also, in a paper of mine published in the Transactions of the Zoological Society (1865), notes of a few Australian marine species. This, I think, represents the sum of our present knowledge respecting the Ostracoda of these regions.

The systematics of parts of the Odontopleuridae are revised using character analyses tracing homologous structures, and a computerised cladistic analysis. The choice of outgroup is shown to affect the result of the analysis. Several synapomorphies place Selenopeltis, the type genus of the Selenopeltinae Hawle & Corda, 1847 as sister genus to Dicranurus. The latter's close relationship to Miraspis, type genus of the Miraspidinae Richter & Richter, 1917 is confirmed. The Selenopeltinae therefore becomes a senior subjective synonym of the Miraspidinae. The Selenopeltinae includes about 90 of the over 380 named odontopleurid species known to date (excluding accepted synonyms). The Ceratocephalinae is recognised, including about 30 species. The paired, large pygidial border spines present in most odontopleurids are in some species not homologous, and a falsifiable hypothesis is proposed for the homology of the ‘true major border spines’. This structure is the posterior pleural spine of the tenth postcephalic segment in selenopeltines, ceratocephalines and odontopleurines, and in acidaspidines and apianurines it is the serially homologous spine of the eleventh postcephalic segment. The spine belongs to the first pygidial segment in all taxa except ceratocephalines, where it is on the last thoracic segment. The homology in selenopeltines of the progressive restructuring of the cheek border is reviewed, explaining the supramarginal appearance of the genal spine. The presence and homology of the sublobation of L1 in odontopleurids is discussed, and it may be homologous with the sublobation in lichids. The strongly differentiated thoracic segmental lengths (exsag.), with maximum length reached in the anterior part of thorax, and the much reduced length of the posterior segments, are aspects of a single character-complex, uniquely derived within the Selenopeltinae. The ontogenetic origin of the anterior and posterior pleural spines is reviewed. The presence in Ceratocephala of two instars in one meraspid degree is discussed. A cladistic analysis of selenopeltine and ceratocephaline genera does not entirely resolve the topology of the phylogenetic tree of these taxa, but it confirms Selenopeltis as sister taxon to Dicranurus. These two genera belong in a clade also including Miraspis, Selenopeltoides, and Ceratonurus. Two new genera are erected, Ceratocara and Archaeopleura, the latter with type species A. kazakhensis sp. nov.

In spite of the structural complexity of polyphase deformed gneisses and migmatites and the absence of distinctive marker horizons, these rocks are amenable to structural investigation and interpretation with resolution of their tectonic history possible, particularly in regions of reasonable exposure. Although methods such as those employing interpretation of stereo-plots can seldom be used, direct observation of refold relationships on the outcrop using all available structural, igneous and metamorphic features will ultimately lead to the resolution of the deformational history. This is achieved by determining the relationships of fold sets observed at the various localities examined throughout the field of investigation and then combining these by correlation according to basic stratigraphical principles. The effects of weak deformation normally not discernible in complicated successions may be detected by the simple form of folded planar and linear structures in igneous masses emplaced in complex structures at intermediate stages in the deformational history.

Synthesis of the total succession and determination of the overall sequence of deformation in particularly complex terranes is made easier if at least one distinctive set of structures can be recognised throughout the area. These key structures have the effect of subdividing the long succession into two in which refold relationships are generally more easily determined. An example of the method is given using photographs from the migmatite terrane in southern Finland.

The uppermost Ordovician (Hirnantian) trilobite fauna of the High Mains Formation in the Craighead Inlier near Girvan comprises species of Flexicalymene, Achatella, Hemiarges, Isotelus and an indeterminate proetid. All are illustrated and the first three including Hemiarges extremus sp. nov. are described. This is one of the most diverse Hirnantian trilobite assemblages known. The beginning of the Hirnantian marked a profound global decrease in trilobite diversity and an overall increase in endemicity with many genera persisting only as local relicts. Many faunas include a dalmanitid (Mucronaspis or Dalmanitina) and the absence of this family suggests a shallow shelf environment for the High Mains fauna which comprises relicts of earlier lineages in the area. Some genera have yet to be discovered in the Hirnantian, but are recorded from both older and younger strata. Like many of the known Hirnantian taxa, they must have survived in localised faunas before becoming widespread again in the Silurian. Limited evidence suggests that the spread of cold/deep water trilobites, notably Mucronaspis / Dalmanitina, on to low latitude shelves preceded the major trilobite extinction at the Rawtheyan-Hirnantian boundary, but this would still be within the timescale suggested by other workers for a rapid onset of the late Ordovician glaciation and the consequent ecological disruption.

Islay and Colonsay occupy a crucial position in the Caledonian frontal zone S of the Great Glen fault in western Scotland. However, some of the stratigraphical units which comprise these islands are of doubtful age as they have tectonic boundaries and contain no fossils or distinctive lithological components. New information is presented here on the deformational histories and styles of the rocks and this has prompted a reassessment of their stratigraphical position and a major reinterpretation of t0he tectonism of this frontal zone.

In contrast to the conventional view, all the stratigraphical units have been deformed together during a regional shearing event. The Colonsay Group contains intrafolial and sheath folds and has a pronounced linear fabric which is parallel to grain elongations in parts of the Bowmore and Dalradian sequences. Most junctions between the Colonsay Group and basement of the Lewisian complex are highly sheared. The junction between the Bowmore Group and Dalradian Supergroup is also tectonised and is normally referred to as the Loch Skerrols thrust but here as a shear zone. This structure is shown not to be a profound discontinuity, alone representing the Caledonian front S of the Great Glen fault, but one element in a major flat-lying NW-directed ductile shear zone. The Caledonian front therefore lies to the W of the islands.

The Bowmore Group is suggested to be a lateral equivalent of the Crinan Grits in the Dalradian Supergroup, lying in the overturned sheared limb of the Islay anticline. The age of the Colonsay Group remains enigmatic; the identification of previously unrecognised early structures which may precede shearing in the Grampian episodes of the Caledonian orogenic cycle allows the possibility of a pre-Caledonian deformation of the Group.

Scorpions from East Kirkton Quarry are represented by abundant cuticle fragments and rarer articulated specimens. Cuticles isolated from their matrix are exquisitely preserved, permitting this fauna to be described in more detail than other Carboniferous scorpion faunas. Most of the material is attributed to Pulmonoscorpius kirktonensis n. gen. n. sp. Specimens possibly indicating the presence of two additional Pulmonoscorpius species are referred to under open nomenclature. Rare fragments of an aquatic ‘archaeoctonoid’, and an orthostern scorpion, also occur. Most specimens of Pulmonoscorpius are juveniles. The range of taphonomic effects observed in these and larger individuals suggests that, as a consequence of poor preservation, the morphology of some Upper Palaeozoic scorpions has been misinterpreted by previous workers. Within the infraorder Mesoscorpionina two groups are recognised. These are distinguished by the position of the posterior pair of coxae. Pulmonoscorpius n. gen. belongs to group A, in which the posterior coxae abut the sternum. This group includes the known Lower Carboniferous mesoscorpions and ranges from the Upper Devonian to the Upper Carboniferous. All group-A mesoscorpions are reviewed here. In group-B mesoscorpions the posterior pair of coxae apparently abut the genital opercula, but confirmation of this derived character and formal taxonomic recognition of these groupings must await a restudy of the group-B mesoscorpions, which are known from the Upper Carboniferous and Triassic.

During the last few years attention has been focussed somewhat sharply upon the Marine Algæ, partly on account of the recently investigated life-histories of some of the larger Phæophyceæ, and partly because of a recent suggestion that the Marine Algæ may represent the stock from which all higher land-plants have originated. Interest has naturally centred on the problem of the origin of an alternation of generations among the seaweeds, comparable to that which has become a characteristic feature in the life-histories of higher terrestrial plants.

Oceanic islands offer outstanding ‘model systems' for investigating long-term dynamics between human populations and their ecosystems. Whilst the state factors involved in human-environment dynamics on islands are often simpler than on continents, the same essential processes are involved. This paper applies a comparative approach to understanding the reciprocal interactions between a set of four Polynesian island cases (Tikopia, Mangaia, Mangareva, Hawaiian Islands), over time scales of between one and three thousand years (kyr). In all cases, the island ecosystems were colonised by Polynesian populations derived from the same ancestral culture, with similar socioeconomic patterns. However, the ecosystems vary significantly in scale, geologic age, and other characteristics. Comparing the historical trajectories of these human–environment dynamics, as revealed by archaeological and palaeoecological study, provides insights into the relative impact of humans on pristine island ecosystems, the influence of environment on ecosystem vulnerability, and the ways in which societies have modified their economies, sociopolitical structures, and other aspects of culture in response to long-term environmental changes.

Cytological results are presented for 60 taxa of Jamaican ferns which supplement information obtained from an earlier survey (Walker 1966). A number of hybrids which form local populations and which may be mistaken for fertile species are described and illustrated. Some species complexes are examined and shown to be more extensive than previously thought. The results presented here are examined in the light of the findings of the earlier survey.

Geochemical data are presented for 166 minor intrusions collected across the axis of the Ardgour swarm in the Isle of Lismore. The intrusions can be divided into: an alkali basalt-camptonite-monchiquite group resembling other Scottish Permo-Carboniferous dykes; a group of calc-alkaline (shoshonitic) lamprophyres, diorites and porphyrites with affinities to the late Silurian-early Devonian appinite suite of Scotland; and Tertiary dolerites. The different groups cannot be unambiguously distinguished in the field and secondary alteration precludes petrographic division in many cases. The data indicate that Caledonian and Permo-Carboniferous lamprophyres have probably been confused in previous accounts of dyke distributions in the region. In Lismore the two groups have identical azimuths but the Caledonian intrusions appear to have a greater aggregate volume. The implications for tectonic and regional models of the area are discussed.

One of the most striking features of the famous Neanderthal cranium consists in the strong projection which is exhibited in the glabellar and the supraorbital or eyebrow regions of the frontal bone. This character is rendered all the more important from the fact that all the specimens which have been collected since the Neanderthal cranium was discovered (1857), and which have been shown to belong to the same remote geological period, possess the same, or at least very much the same, remarkable prominence in the eyebrow region. These specimens are not very numerous, but, inasmuch as they represent the earliest remains of man with which we are acquainted, they possess a very special interest. In addition to the Neanderthal cranium, the group includes the two Spy crania, the Gibraltar skull, and the recently discovered Krapina remains. The Krapina remains are in a very fragmentary condition, but they apparently consist of portions of the skeletons of ten individuals, and the frontal bones all present the character in question.

U–Pb isotopie data for zircons from a granulite-facies xenolith from a volcanic vent at Partan Craig in the southeastern part of the Midland Valley of Scotland display evidence of an early Proterozoic (>2·0 Ga) component. The xenolith is probably relict metasediment and the data therefore indicate old detritus in the sedimentary precursor. The exact ages of sedimentation and metamorphism are uncertain but these must be compatible with Sm–Nd data on similar xenolithic fragments from the same locality which constrain the ages to c. 1–0 Ga or younger.

Twenty six of the more important species of monograptids (s.l.), retiolitids and Cyrtograptus (from a total fauna of 52 species) are described from Wenlock strata of the Cape Phillips Formation, Canadian Arctic Archipelago. Of this fauna, eight new species or subspecies, Monograptus firmus festinolatus, M. instrenuus, M. opimus, M. testis incomptus, Cyrtograptus falcatus, C. hamatus brevis, C. kolobus and C. pseudomancki, are described and illustrated.

Wenlock biostratigraphic zones comprise the Cyrtograptus centrifugus-C. insectus Zone (earliest Wenlock), M. instrenuus-C. kolobus Zone, tentatively divisible into lower and upper subzones, C. perneri-M. opimus Zone possibly divisible into lower and upper subzones, C. lundgreni-M. testis Zone divisible into a lower M. testis incomptus Subzone and an upper M. testis testis Subzone, and the Pristiograptus ludensis Zone (latest Wenlock).