Abundant microvertebrate remains from the Siberian Platform are described as early acanthodians. All are preserved with both excellent morphology and histology. They are assigned to a new order, Tchunacanthida, with two new families, Lenacanthidae and Tchunacanthidae. These comprise two new genera, Lenacanthus and Tchunacanthus with type species L. priscus sp. nov. and T. obruchevisp.nov. The evidence from the morphology and histology is that they are the most ancient acanthodian scales so far found. The total collection of vertebrate material from the Irkutsk amphitheatre is described, together with their geological distribution, geographical range and systematic palaeontology. Head scales, tesserae of three morphotypes, transitional scales and body scales have been found. All comprise morphological sets as determined by comparison of morphology using SEM and of histology using Nomarsky interference optics. Observations of growth were possible from details of concentric lines on the crown and also from incremental layers seen in both horizontal and vertical sections. Starting from the primordial scale, consecutive layers are added, coronally, laterally, and deep in the corium onto the base; these occurred simultaneously in both crown and base. A type of areal-superpositional growth occurred in some body scales but in other scales there was little superpositional growth. It is concluded that Tchunacanthus possessed very solid body armour with tightly joined scales covering a large area of the body, and scale bases deeply set in the corium. Both tissues of the scales, dentine and bone, feature enclosed cells. This character is regarded as primitive within acanthodians, as in derived forms both tissues are acellular. Acanthodian scales are one of many examples of transformation from cellular to acellular tissue in evolution.

The Eleonore Bay Supergroup (EBG) is a 16 km-thick shallow-water sequence of Neoproterozoic age that is preserved within the East Greenland Caledonides in several tracts, surrounded by crystalline gneisses and schistose supracrustal rocks. The apparent downward transition from non-metamorphic EBG into gneiss gave rise to the classic ‘stockwerke’ hypothesis, in which all the metamorphism was regarded as Caledonian, and differences in grade were ascribed to the ascent of a migmatite front to different levels within the orogen. Field and isotopic studies in the 1970s however revealed that the underlying gneisses and schists had undergone orogenic reworking in mid-Proterozoic time; the EBG–basement contact was then interpreted as an approximately bedding-parallel décollement with apparent lag geometry, that is with EBG cover rocks in its hangingwall.

Recent work in the northernmost EBG tract, at Ardencaple Fjord, has shed light on the problems posed by the basal relationships of the EBG, and together with regional structural and stratigraphic data leads to the following interpretation. There are two regionally important basement-cover interfaces within the East Greenland Caledonides. The earlier one is between Archaean/early Proterozoic gneisses and early Proterozoic supracrustal rocks, which were pervasively deformed in mid-Proterozoic time and form the basement to the Neoproterozoic Eleonore Bay cover sequence. This was deposited on a vast, continually subsiding shelf that is now preserved in East and NE Greenland and Svalbard, and contains Grenville detritus. EBG deposition was terminated by major extensional faulting of Vendian age; the succeeding Tillite Group is interpreted as a syn-rift sequence, presumably associated with the opening of Iapetus.

The EBG–basement contacts that are not late faults are inferred to be extensional shear zones of Vendian age. These were reactivated in compression during the Caledonian orogeny in the Silurian, with metamorphic and fabric convergence, which accounts for the apparent downward transition from sedimentary rocks through schists into gneisses. Caledonian shortening was not large; inversion of the Vendian grabens was incomplete, so that the marginal shear zones retained their lag geometry and large tracts of low grade Eleonore Bay sediments are preserved at the present erosion level, surrounded by Proterozoic basement rocks, within the Caledonian belt of East Greenland.

Bellerophontidæ occur in considerable numbers at certain horizons in the Scottish Carboniferous rocks. Many forms are represented, but few have been described or figured (see Historical Account, Section III). In undertaking the study of these fossils the writer's object was limited, primarily, to figuring and describing the Scottish forms and ascertaining their value as stratigraphical indices in the Scottish Carboniferous rocks. Many forms from the shaly facies have been recorded in Scottish stratigraphical literature under the names of English and Belgian species of limestone facies. Investigation proved that most of these records were invalid, the determinations being erroneous, and that revision of all the Anglo-Belgian Bellerophontidæ was necessary in order to define the Scottish forms. The present memoir embodies the results of the wider investigation.

Ossified skeletal elements within the orbit, such as scleral ossicles, palpebrals, supraorbitals and sesamoids, are widespread across Reptilia, including extant members of Crocodylia, Aves, Squamata and Chelonia. Extant crocodylians lack scleral ossicles, but have a unique palpebral that has recently been shown, through developmental studies, to be an osteoderm in the upper eyelid. Here, we examine the diversity and disparity of the crocodylian palpebral in extant members of Crocodylia and, through the fossil record, trace the origin and evolutionary history of the element throughout Pseudosuchia (all archosaurs more closely related to crocodylians than avians). We show that the crocodylian palpebral originated outside of Crocodylomorpha in early pseudosuchian groups (e.g. Aetosauria, Loricata) and that scleral ossicles are lost in nearly all groups of pseudosuchians, but appear in poposauroids, at least one early crocodylomorph, and some partially or fully marine Crocodyliformes (e.g. thalattosuchians). The morphology and number of palpebrals differs across Crocodyliformes; the presence of two palpebrals is plesiomorphic, but this is reduced to one by Crocodylia. We further recommend the restriction of the term palpebral to the structure in crocodylians and their homologues, but not to the structure in ornithischian dinosaurs.

During the course of experiments on the toxic effects of tetrachlorethane on minnows, Phoxinus phoxinus (L.), Mr J. Wilson Dougal, B.SC., found “cellular bodies” in a portion of the brain tissue of a dead minnow which he had spread on a microscopic slide. Sections of the head of the minnow were subsequently made by Mr Richard Muir and submitted to me for an opinion on the nature of the bodies. Examination showed that they were immature Trematodes of the family Holostomidæ. I handed the sections and a living minnow, sent at the same time (May 1923), to Miss Bannerman for further study, remarking that the only Trematode hitherto recorded as occurring in the brain of fresh-water fish in Britain was a Tetracotyle in the brain of the lamprey and the ammocœte. I subsequently directed her attention to Mataré's account (1910) of a similar worm which had been found in the brain of minnows collected in Switzerland and in Germany. Miss Bannerman studied numerous examples of the parasite during June and July 1923 and in September 1925, but she had to leave in October 1925, before the work could be completed, to take up a post in India. The comparison with previously recorded species of Tetracotyle, the discussion on the morphology of the ventral sucker, the account of the excretory canals, and a number of details in other parts have been added since she left.—J. H. A.

The granites of Hong Kong comprise a variety of assemblages dominated by chemically evolved compositions. They are divided into two suites based on petrographic, geochemical, and age criteria. The oldest and most primitive intrusive units are deformed biotite-hornblende granodiorites and monzogranites of the Lamma Suite. These rocks are characterised by high CaO (1·4-2·7%), and low Nb and Y contents. The Lion Rock Suite (LRS) is dominated by relatively undeformed monzogranite with subordinate quartz syenite and comprises three subgroups. Granites of subgroup I are separated into coarse- and fine- to medium-grained lithologies. The fine- to medium-grained granites are predominantly fluorite-bearing with silica contents ranging from 75·5-78%. They are characterised by high total REE, Ga, F, Rb, Nb, and Y contents and yield a Rb-Sr whole-rock isochron age of 155 ± 6 Ma with an initial 87Sr/86Sr ratio of 0·7101 ± 0·0060 (MSWD = 4·6). Granites of subgroup II comprise a diverse range of compositions (SiO2 = 63–77%) and are characterised by highly variable trace element abundances. Coarse-grained granites yield an age of 148 ± 9 Ma with an initial 87Sr/86Sr ratio of 0·7060 ± 0·0006 (MSWD = 0·1). Granites of subgroup III are moderately to highly evolved (SiO2 = 72·5-77·9%) and the silica-rich compositions are marked by enrichment in Y, Nb, Rb and depletion in Ba and Sr. Rb-Sr whole-rock isochron ages for individual plutons vary from 138 ± 1 to 136 ± 1 and corresponding initial 87Sr/86Sr ratios are 0·7080 ± 0·0002 (MSWD = 1·2) and 0·7092 ± 0·0006 (MSWD = 0·4). Granites of the Lamma Suite and coarse-grained granites of LRS subgroup I are interpreted as synorogenic I-types, whereas those of LRS subgroups II and III are interpreted as late-orogenic to postorogenic, fractionated I-types. Fineto medium-grained granites of LRS subgroup I have distinctive A-type affinities and together with their association with quartz syenite indicate a transition from compressional to tensional tectonics.

Dehydration melting of crustal rocks may commonly occur in response to the intrusion of mafic magma in the mid- or lower crust. However, the relative importance of melt buoyancy, shear or dyking in melt generation and extraction under geologically relevant conditions is not well understood. A numerical model of the partial melting of a metapelite is presented and the model results are compared with the Ivrea-Verbano Zone in northern Italy. The numerical model uses the mixture theory approach to modelling simultaneous convection and phase change and includes special ramping and switching functions to accommodate the rheology of crystal-melt mixtures in accordance with the results of deformation experiments. The model explicitly includes both porous media flow and thermally and compositionally driven bulk convection of a restitecharged melt mass. A range of melt viscosity and critical melt fraction models is considered. General agreement was found between predicted positions of isopleths and those from the Ivrea-Verbano Zone. Maximum melt velocities in the region of porous flow are found to be 1 × 10−7 and 1 × 10−1m per year in the region of viscous flow. The results indicate that melt buoyancy alone may not be a sufficient agent for melt extraction and that extensive, vigorous convection of partially molten rocks above mafic bodies is unlikely, in accord with direct geological examples.

The migmatite complex of the Savonranta district of eastern Finland represents the combined effects of polyphase deformation, polymetamorphism and the emplacement of a series of dioritic, grandioritic, granitic and pegmatitic masses. The most significant feature in terms of both regional structure and control of neosome emplacement is a large wrench fault zone along which there has been a minimum of 30 km displacement. Its development was controlled by a stress system related to plate movement in the early-middle Proterozoic Svecokarelian orogenic belt.

Successive neosome development has been related to the extensive structural and metamorphic history of the amphibolite facies palaeosome mica schists which has been deduced from refolding and cross-cutting relationships. Rb–Sr whole-rock isotopic studies of a porphyritic granite, whose emplacement was controlled by the wrench fault regime, indicate an age of crystallisation of 1786 ± 80 m.y. The initial 87Sr/86Sr ratio of 0·7053 ± 01 shows the source region for the granite magma had a previous crustal history.

1. The integral occurs so frequently in various branches of research that, as far back as 1783, Laplace suggested that it would be useful to tabulate its values for successive ranges of integration. It is employed in investigations on the theories of refraction, conduction of heat, of errors of observation, of probabilities, etc. These are familiar to physicists and need not be dwelt upon.

In the 'eighties of last century R. G. Symes and A. McHenry mapped the schists of Antrim for the Geological Survey of Ireland. They made abundant records of dip, which are still valuable though, owing to the difficulty of the subject, not uniformly reliable. They also indicated outcrops of limestone at Torr Head and, 8 miles inland, at Glenshesk and Breem. The schist area of Antrim is contained in Sheets 8 and 14 of the one-inch to the mile Geological Survey Map of Ireland (text-fig. 1).

Though a great deal has been written on the Eurypteridæ, and many points of their anatomy elucidated in the brilliant memoirs of Huxley and Salter, Hall, Woodward, Schmidt, &c, nevertheless many points of morphological importance remain obscure. This is perhaps to be attributed to the fact that nearly all the writers on this group have treated them rather from the systematic than the morphological standpoint. In dealing with remains so fragmentary and obscure as the majority of these fossils are, the value of some theory as to their relations among recent forms is enormous, both as suggesting points to be looked for and aiding in the interpretation of structures observed. The greater part of the work on this group was done before the arachnid relationship of Limulus was fully appreciated, and it is in the light of a possible relationship to this form, and also to the lower orders of terrestrial Arachnida, that it seemed to me to be worth while to revise the anatomy of the group. It has been necessary to include a certain amount of what is already well known in the description of the different genera, and I have taken special care to confirm, as far as possible, points which seemed to me to rest on insufficient grounds.

The phenomena of the cyclic changes in the human and other mammalian uteri have at all times been a subject arousing interest, inviting speculation, and stimulating investigation. It is therefore somewhat curious that from the plethora of literature concerned in great measure with the histological and physiological interpretations of these phenomena relatively little information is to be obtained concerning the part played by rhythmic variations of the vascular architecture.

Non-hadrosaurid iguanodontians were the most diverse and abundant group of large-bodied herbivorous dinosaurs during the Early Cretaceous, and were a particularly important component of Laurasian ecosystems. Recent years have seen a dramatic increase in our knowledge of the diversity of this group, with multiple new taxa being described from northeast China. The most complete of these Chinese non-hadrosaurid iguanodontians is Jinzhousaurus yangi, from the middle part of the Yixian Formation (Lower Cretaceous: lower Aptian) of Liaoning Province. Here, we provide the first description of the relatively complete and partially articulated postcranial skeleton of the holotype of Jinzhousaurus, and provide detailed comparisons to closely related taxa. We document additional autapomorphies of Jinzhousaurus that provide strong support for the validity of this taxon.

The proper temperature of our globe is a question which, formerly abandoned to speculation and hypothesis, has only lately been made the subject of direct experiment. Preliminary to it, and intimately connected with it, is another inquiry of great interest, namely, What is the thermometric effect of the whole solar heat which falls in a year on the surface of the globe ? How much is transmitted to the interior? How much dissipated at the surface? To what depth does the influence of the seasons extend, and in what manner is that influence modified at different depths? It is impossible to say to how many curious and important inquiries a solution of these preliminary questions may lead the way; and it is to them that our attention is at present to be confined. We shall not speak, except incidentally, of the absolute heat of the interior of the globe; we shall only discuss the modifications of the solar heating influence near its surface.

Shortly after my arrival in Britain in December 1911 I was honoured by a request from Dr W. S. Bruce, leader of the Scottish National Antarctic Expedition, that I would prepare a report on the Amphipoda collected during the voyage of the Scotia. Dr E. J. Allen, Director of the Marine Laboratory, Plymouth, very kindly offered me accommodation in the laboratory for the work, and free access to the library of the laboratory, which, fortunately, is very well supplied with works on the Crustacea. I was assured also of assistance from Mr T. V. Hodgson, the Curator of the Museum and Art Gallery, Plymouth, from Mrs E. W. Sexton, and from other friends; and accordingly I undertook the work. I received the main portion of the collection, contained in sixty-three bottles, on the 8th January 1912, and a few days later I received from Dr W. M. Tattersall of the Manchester Museum eighteen tubes containing additional Amphipoda found among the Schizopoda of the Scottish National Expedition which had been submitted to him for determination; these additional specimens contained three or four species not represented in the collection first received.

1. By a knot of n crossings, I understand a reticulation of any number of meshes of two or more edges, whose summits, all tessaraces (ἀκή), are each a single crossing, as when you cross your forefingers straight or slightly curved, so as not to link them, and such meshes that every thread is either seen, when the projection of the knot with its n crossings and no more is drawn in double lines, or conceived by the reader of its course when drawn in single line, to pass alternately under and over the threads to which it comes at successive crossings.

The Viséan sequence at East Kirkton contains abundant plant fossils which show a wide range of preservation states. Most of the plant fragments are allochthonous, but stigmarian rootlets are found in situ at the top of the sequence and form mats near the base, where they are preserved in cherts. Axes have commonly been reworked within tuffs at the base. The majority of the plants are preserved as fragmentary compressions, although mineral replacement of the organic matter has occurred in some places. A number of woody axes which have been permineralised by phases of calcite and silica are found in the limestone and tuffs of the sequence. These axes often show complex mineralisation patterns and can occur at the centre of stromatolitic nodules. Some are well preserved and appear to have been permineralised rapidly whereas others show evidence of decay prior to calcite growth or degradation after stromatolite developed. Fusain (fossil charcoal) is abundant in the sequence, in addition to fusain transition fossils caused by partial charring, which suggests the occurrence of palaeowildfires in the area. The plant fossils have been assigned to a number of categories (some of which are new), based on their varied preservation states.

The Stephanian Konservat-Lagerstätte of Hamilton, Kansas, deposited in a marine-estuarine environment preserves a mixture of terrestrial, fresh-water, and marine fossil organisms. The marine component is the most diverse taxonomically, whereas one ostracod species, commonly interpreted as a fresh-water form, together with vascular plant debris dominates volumetrically. Well-preserved terrestrial and aquatic vertebrates and arthropods were embedded in rapidly deposited calcareous mud conducive to microbial early-diagenesis of vertebrate soft tissues in a tidal estuarine setting. Many vertebrate fossils show no evidence of preburial decay or disarticulation. Dark-coloured body silhouettes (‘skin preservation’) are composed of calcitic bacteria, calcite crystals and organic material, and have been interpreted to reflect preservation under saline conditions. The aquatic vertebrates had a broader tolerance of salinity than today. The fishes were perhaps migratory (anadromous or catadromous), and some used the estuarine environment for spawning. The tetrapods (dissorophid amphibians) retained their tolerance to salinity from their marine ancestors and were able to spawn in near-shore environments. The terrestrial biota was dominated by the conifer Walchia and was subjected to forest fires, as evidenced by preserved charcoal fragments.

Plants of gymnospermous affinities are the most important component of the flora at East Kirkton. Four genera of anatomically preserved gymnosperm stems with well developed secondary xylem are interpreted as arborescent. The largest specimens (trunks up to 50 cm in diameter) are attributed to the genus Pitus. Features of the wood, including ray size, are characteristic of the species Pitus withamii Lindley & Hutton which has long been described from the Strathclyde (former Oil-Shale) Group of Scotland. Decorticated axes of Eristophyton fasciculare are more common; their study has enlarged our concept of the species with regard to maximum diameter, internode length and phloem organisation. Similarly, the decorticated specimens of Bilignea solida Kidston found at East Kirkton exceed in diameter the original material described from Ayrshire. The fourth taxon is Stanwoodia recently described by Galtier and Scott (1991). In all these plants, features of leaf traces suggest that leaves were relatively large and densely borne on ultimate branches. These leaves were shed ultimately, prior to a later phase of wood development; they certainly correspond to (? most of) the compression foliage commonly found in association: Sphenopteridium, Adiantites and Spathulopteris.

Early Proterozoic rapakivi intrusions in S Greenland occur as thick sheets which have ramp–flat geometry and were intruded along the median planes of active ductile extensional shear zones. These shear zones and their intrusions were linked via transfer zones in a major three-dimensional framework. At high structural levels (c. 6 km) the rapakivi intrusions developed thermal aureoles which overprint the regional assemblages, whereas at deeper levels in the regional structure they are contemporaneous with regional metamorphism. Thermobarometry on the regional and contact assemblages indicates low pressure granulite facies conditions (200–400 MPa, 650°-800°C) suggesting very high thermal gradients. The rapakivi suite and associated norites have low initial 87Sr/86Sr together with positive εNd values, indicating the involvement of predominantly young crust and/or mantle component in the generation of the igneous suite. It is considered that the voluminous norites are closely related to the mafic melts which underplated the juvenile crust to trigger the generation of the monzonitic rapakivi suite. Taken together, the data are consistent with a model of Proterozoic lithospheric extension, thinning of relatively juvenile continental crust and compression of mantle isotherms, resulting in high crustal heat flow, mafic underplating, and crustal melting with emplacement of magmas along a linked network of extensional shear zones.