The Cooma Complex of southeastern New South Wales comprises an andalusite-bearing S-type granodiorite surrounded by migmatites and low-pressure metamorphosed pelitic and psammitic sediments. The migmatite formed by the melting reaction:

Biotite + Andalusite + K-feldspar + Quartz + V = Cordierite + Liquid

at about 350–400 MPa , 670-730°C.

The melanosome consists of biotite + cordierite + andalusite + K-feldspar + plagioclase + quartz + ilmenite, whereas the leucosome consists of cordierite + K-feldspar + quartz with extremely rare biotite and plagioclase. In a closed system, freezing of the leucosome melt patches should have resulted in cordierite back-reaction with melt to produce biotite and andalusite. The virtually anhydrous mineralogy of the leucosome patches, lack of cordierite reaction and the absence of biotite selvedges at the leucosome-melanosome contacts, indicates that the melt did not completely solidify in situ. These observations can be explained by an initial peritectic melting reaction in the migmatite being arrested from back-reaction upon cooling because of the removal of hydrous melt, enabling leucosome cordierite to escape back-reaction. We propose that the melanosome is the residue of partial melting but that the leucosome patches do not represent frozen melt segregations but rather the liquidus minerals (cumulates) which precipitated from the melt.

In the restite-rich granodiorite from the core of the Cooma Complex, cordierite of similar composition to that in the migmatite has reaction rims of biotite and andalusite and there are coexisting biotite and andalusite in the matrix. The granodiorite consisted of about 50 wt% melt together with resite biotite, quartz and plagioclase, which can possibly be identified in the surrounding migmatite. Previous work suggested that the Cooma Granodiorite can be derived from a mixture of the surrounding metasediments which are of similar composition in the high and low-grade areas surrounding the granodiorite. Re-examinatibn of those data shows that the high-grade metasediments are more An-rich than the low-grade rocks. The Cooma Granodiorite is very similar to the high-grade rocks in terms of Or-Ab-An ratio. This suggests derivation of the Cooma Granodiorite from the high-grade rocks and not from the relatively An-poor low-grade rocks which are typical of exposed sediments in the Lachlan Fold Belt. It is most likely that the granodiorite and envelope of high-grade rocks have been emplaced into the compositionally different lower grade rocks from slightly greater depths.

Rare garnet phenocrysts and garnet-bearing xenoliths occur in high-silica, metaluminous to peraluminous andesites and dacites (and their high-level intrusive quartz diorite equivalents) from a Miocene calc-alkaline province in Northland, New Zealand. These garnets are among the most Ca-rich (17–28 mol% grossular) garnets of igneous origin so far recorded in calc-alkaline suite rocks. Associated minerals are dominant hornblende and plagioclase and minor augite, occurring as phenocrysts in xenoliths and as inclusions in the garnet. This mineralogy points to the I-type character of the garnet-bearing host magma compositions, and contrasts this garnet occurrence with the more frequently recorded grossular-poor (3–10 mol%) garnets with hypersthene, plagioclase, biotite and cordierite, found in S-type volcanic and intrusive host rocks.

Detailed experimental work on a glass prepared from one of the garnet-bearing dacites closely constrains the conditions under which the natural phenocryst and xenolith mineral assemblages formed. This work was conducted over a pressure-temperature range of 8–20 kbar, 800–1050°C with 3–10 wt% of added H2O, defining overall phase relationships for these conditions. Importantly, amphibole only appears at temperatures of 900°C or less and clinopyroxene at >900°C (with 3wt% H2O). Orthopyroxene occurs with garnet at lower pressure (∼15 kbar with 3wt% H2O; ∼>10kbar with 5wt% H2O). Absence of orthopyroxene from the natural garnet-bearing assemblages indicates pressures above these limits during crystallisation. Plagioclase is markedly suppressed (with respect to temperature) with increasing H2O content, and for pressures of 10–15 kbar, the maximum H2O content possible in the magma with retention of clinopyroxene and plagioclase together (as evident in xenoliths) is 5–6 wt%. Finally, the lack of quartz in any of the xenoliths suggests magma H2O content higher than 3% (where quartz appears with amphibole at 900°C), since the quartz liquidus temperature decreases with increasing H2O content, and with decreasing pressure. In experiments with 5wt% H2O, a quartz-free field of crystallisation of garnet-clinopyroxene-amphibole-plagioclase occurs between 10 and 15 kbar and temperatures between 850 and 900°C. In addition, detailed experimentally-determined garnet compositional trends, together with ferromagnesian mineral compositional data for specific experiments with 5 wt% H2O added and run at 10-13 kbar and ∼900°C, suggest that the natural assemblages formed at these conditions. This implies that the parental dacitic magma must have been derived at mantle depths (the Northland crust is ∼25 km thick), and any basaltic or basaltic andesite precursor must have contained ∼2–3 wt% H2O.

The unique nature of the Northland volcanics and high-level intrusives, preserving evidence of relatively grossular-rich garnet fractionation in the high-pressure crystallisation history of an originally mantle-derived magma, is attributed to a combination of unusually hydrous conditions in the source region, complex tectonic history involving obduction and subduction, possible incorporation of crustal slivers in a mantle-crust interaction zone, and relatively thin (∼25 km) crust.

Among Gasteropod Molluscs the life-histories and development of the most highly evolved members, the terrestrial Pulmonates, have been less intensively studied than those of more primitive aquatic forms. This has been due in part to the technical difficulties involved in the permanent preparation of material for study, and in part to the fact that the investigator seeking for primitive features of phyletic interest is more likely to find these among more generalised species of Gasteropods than among those which are obviously adapted, both during the early stages of their development and in adult life, to a habitat far removed from the ancestral one.

It is the purpose of this paper to present data bearing upon the life-history of a single species of land Pulmonate, Agriolimax agrestis L., to enlarge upon certain aspects of the embryology of this species, and to demonstrate the structural and functional changes of the larva which have accompanied the transition from an aquatic to a terrestrial breeding habit.

During experiments conducted within the vent pool of Medusa Geyser, Norris Geyser Basin, Yellowstone National Park, USA, amorphous opaline silica (opal-A) was deposited on/within plant tissues within 30 days of immersion. Initially, deposition created inter/intra-cellular films which lined cell walls plus intercellular colloid suspensions (sols) of opal-A nano/microspheres. By 330 days, opal-A deposition created a robust external and internal matrix that stabilised tissues against collapse and replicated plant structure. Opal-A films increased to micron-order thicknesses and intracellular sols were created. Systematic variation of opal-A fabric between tissues comprising living/dead cells at the time of deposition indicate that cell function, architecture and shape influence fabric development. Heterogeneity of opal-A fabric within adjacent cells of similar structure/function indicates spatially/temporally fluctuating physicochemical conditions and the presence of intraorganic microenvironments. Early deposition of opal-A films suggests a period of low silica supersaturation and slow opal-A deposition. In contrast, intracellular sols suggest high levels of supersaturation, and rapid opal-A deposition. Shell-like microsphere growth suggests cyclic variation of silica supersaturation, and alternations between rapid and slower opal-A deposition. Microsphere growth to the upper limit of colloidal stability and colloidal crystal structures indicate prolonged sol stability, whilst floc-like microsphere networks indicate localised sol instabi

Fossils in the Pragian Rhynie cherts, Aberdeenshire, Scotland, are preserved with exquisite cellular detail, and provide much information on Early Devonian terrestrial and freshwater ecosystems. The fossils include abundant and diverse coprolites which demonstrate the existence of consumers differing in life-habit and diet. The coprolites are small (0.5–3 mm) and diverse in morphology and content, including groups of amorphous coprolites as well as coprolites with identifiable, particulate content. The present authors define three new ichnogenera to accommodate these coprolites:

• • Lancifaex encompasses elongate coprolites with particulate content, and includes three ichnospecies, distinguished on morphology, L. simplex, L. divisa and L. moniliforma.

• • Rotundafaex encompasses rotund coprolites with particulate content, and includes a single ichnospecies, R. aggregata.

• • Bacillafaex encompasses rod-shaped coprolites with amorphous content, and includes two ichnospecies, distinguished on size, B. constipatus and B. mina.

These notes on Arctic Tardigrada embody the results of an examination of quantities of moss collected by Mr William S. Bruce on his various expeditions to the Arctic Regions.

While studying the Tardigrada of the Scottish lochs, I wished to compare our Tardigrade fauna with that of more northern lands, as it was thought that, considering the geographical position of Scotland, its fauna might have some relation with that of those lands. Mr Bruce was kind enough to put all his available material at my disposal.

The Windyfield chert site is located 700 m NE of the original Rhynie chert locality at Rhynie, Aberdeenshire, Scotland. Originally identified by concentrations of surface float material, a drilling and trenching programme of the area in 1997 revealed a chert ‘pod’ in situ interbedded with fluvial/lacustrine sandstones and hydrothermally altered shales. Chert morphologies identified from float blocks and trench material range from tabular beds to lenticular pods displaying massive, nodular, laminated and brecciated fabrics, and geyserite splash textures. A suite of floral and faunal associations, when combined with distinctive macro- and microscopic chert textures, has been used to interpret depositional conditions. Palaeoenvironments ranged from terrestrial laminated, brecciated and vegetated sinter sheets to low-temperature pools and marginal aquatic settings. The flora comprises six higher land plant species, nematophytes, charophytes, various fungi and probable cyanobacteria. Arthropods include branchiopod crustaceans, a euthycarcinoid, trigonotarbid arachnids, centipedes, eoarthropleurids and a possible hexapod. The biota of the Windyfield chert is closely comparable to that found in the Rhynie chert. Together, the Windyfield and Rhynie cherts contain the most diverse associated fossil arthropod fauna of terrestrial and freshwater origin from rocks of comparable age anywhere in the world.

Since 1912 I have had the intention of re-examining all the available material of palæozoic amphibia, and have done so personally in the case of the Labyrinthodontia, and through my students Drs Bulman, Whittard, and Steen for the Branchiosaurs, and all the small animals from the famous localities of Czechoslovakia; Linton, Ohio; and South Joggins, Nova Scotia. But these researches, although they have included as complete an account as can be made of Hylonomus lyelli, the first animal called a Microsaurian, still left us without a clear conception of that group, if indeed it has any real existence.

Last year, however, Dr Steen was able to show that Microbrachis and Hyloplesion from the Upper Coal Measures of Nýřany were related to Hylonomus and were Adelospondyli.

It therefore became important to examine the well-preserved skeleton, from the Coal Measures of Mazon Creek, Ill., which R. L. Moodie described and restored as a Microsaur. The unexpected results form the paper which follows.

The types and undescribed material of the hymenopteran fossils of the Insect Bed of the Bembridge Marls from the Isle of Wight (UK) are critically revised and studied. A total of 1460 fossils are recorded and attributed to 20 families: Gasteruptiidae s.l. (1); Proctotrupidae (3); Diapriidae (24); Cynipidae (7); Figitidae (6); Pteromalidae (1); Agaonidae (3); Scelionidae (12); Platygastridae (2); Ichneumonidae (32); Braconidae (75); Bethylidae (3); Crabronidae (2); Sphecidae (1); Apidae (2); Scoliidae (1); Tiphiidae (2); Vespidae (4); and Formicidae (1220). Described as new are 51 species, 13 genera, two tribes and two subfamilies. Minimum number of species recorded (either as described species or representing higher taxa with no described species in the assemblage) is 118. The composition of the hymenopteran assemblage is most similar to that of Baltic amber and indicative of a well forested territory, as well as of a humid, equable (aseasonal but not very hot) climate, more typically equable than in the Baltic amber source area, judging from the absence of Aphidiinae and scarcity of aphids.

The spatially fixed sporophyte body of vascular land plants has to be adapted to both atmospheric and substrate environments. Potentially almost all stages in the life cycle of a land plant are fossilisable and the physiological adaptations to these environments are reflected in the morphology, anatomy, and chemistry of the plant. Although solutions to the plant's physiological problems have been refined through evolution, the basic responses to fundamental environmental parameters such as temperature, water availability, nutrient supply, gas exchange and light, evolved early in land plant history. These taxon-independent solutions can be used qualitatively, and sometimes quantitatively, to track changes in atmospheric and edaphic conditions throughout much of the Phanerozoic. Increase in body size and height in Middle and Late Devonian times was coupled with intense demand for light, nutrients and water supply and with elaborations of vascular systems, photosynthetic surfaces, organ abscission and ‘root’ organisation. During the Carboniferous extreme adaptations to substrate waterlogging evolved. Mycorrhizal associations and “phi” layers in Triassic roots represent early aspects of modern root physiology. From the mid-Cretaceous, angiosperms exhibit leaf architectural characteristics which in modern plants relate qualitatively to moisture and light, and quantitatively to temperature, while vessel size and distribution in trunk wood is related to water stress and susceptibility to freezing. The relative proportion of plants utilising C3, CAM, and C4 photosynthetic pathways varies with environment. Isotopic analysis of plant fossils may demonstrate changing relative frequencies of photosynthetic pathways through time in relation to atmospheric composition and temperature.

The development of the skeleton of the small temnospondyl Acanthostomatops vorax is described, based on 32 specimens from the Lower Rotliegend of Niederhäslich in Saxony. Both individually and ontogenetically, the skull table, length of gape, and dentition of the parasphenoid are broadly variable. The stapes has a short and straight shaft and a well-defined two-headed proximal region. Small specimens have three or four pairs of ossified ceratobranchials in the gill region, while the adult hyobranchium is composed of four pairs of hypobranchials and probably some additional elements. The postcranium is characterised by a stout and well-ossified humerus that is already large in small larvae, a minute rectangular interclavicle, a robust but short femur, a relatively short trunk with 21–22 presacrals and a moderate tail with 28 vertebrae. In adults, the trunk skeleton became proportionally shorter and the femur smaller with respect to skull length. Metamorphosis is best indicated by the disappearance of the larval gill skeleton, which was probably resorbed, while the structure of the limbs and axial skeleton as well as the absence of lateral line sulci suggest a terrestrial existence for adults.

Using the ion microprobe SHRIMP we have analysed zircons from the Ben Vuirich, Glen Kyllachy, Inchbae and Vagastie Bridge granites from the Scottish Caledonides, in an attempt to resolve the ages of inherited zircons shown to be present in these granites by previous conventional multigrain analyses. Middle Proterozoic age components were found in inherited zircons from all four granites. Late Proterozoic (900–1,100 Ma) components have been identified in zircons from the Glen Kyllachy and Ben Vuirich granites in the Grampian Highlands. A Late Archaean age has only been detected in one zircon from the Glen Kyllachy granite. The distribution of inherited components in the granite zircon populations could reflect fundamental divisions in the age composition of granite source rocks; however, detailed assessment of this possibility must await further ion microprobe analyses on zircons from many more granites.

SHRIMP isotopic and U, Th and Pb analyses were made on successive shells of zoned zircon surrounding inherited cores from the Glen Kyllachy granite to monitor chemical changes during magmatic zircon growth. Results show that zircon shells have characteristic but significantly different Th, U and Pb concentrations. Magmatic zircon from the Vagastie Bridge granite also forms as clearly defined oscillatory zoned shells around unzoned nuclei of inherited zircon. However, the distinction between magmatic and inherited zircon in zircons from the Inchbae granite is less clear. Zircons from the Ben Vuirich granite occur as euhedral, magmatic zircons, or as rounded, subhedral, inherited zircon grains. A SHRIMP age of 597 ± 11 (2σ) Ma for euhedral magmatic zircon from this granite is identical, within the uncertainty, to the conventional multigrain zircon age of 590 ± 2 (2σ) Ma reported by Rogers et al. (1989) and confirms the conclusions of those authors that sedimentation of the Dalradian sequence took place in the Precambrian.

Brief descriptions and comments on relationships are given for the seven embryophytic sporophytes in the cherts at Rhynie, Aberdeenshire, Scotland. They are Rhynia gwynnevaughanii Kidston & Lang, Aglaophyton major D. S. Edwards, Horneophyton lignieri Barghoorn & Darrah, Asteroxylon mackiei Kidston & Lang, Nothia aphylla Lyon ex Høeg, Trichopherophyton teuchansii Lyon & Edwards and Ventarura lyonii Powell, Edwards & Trewin. The superb preservation of the silica permineralisations produced in the hot spring environment provides remarkable insights into the anatomy of early land plants which are not available from compression fossils and other modes of permineralisation. They include soft tissues, such as those surrounding stomata, rhizoids, apical and lateral meristems, and diversity in conducting cells, with inferences for palaeoecophysiology, including water use efficiency, transport and absorption, and for growth processes and patterns.

The ecological ranges of Archaeobacteria and Eubacteria are constrained by a requirement for liquid water and the physico-chemical stability limits of biomolecules, but within this broad envelope, prokaryotes have evolved adaptations that permit them to tolerate a remarkable spectrum of habitats. Laboratory experiments indicate that prokaryotes can adapt rapidly to novel environmental conditions, yet geological studies suggest early diversification and long-term stasis within the prokaryotic kingdoms. These apparently contradictory perspectives can be reconciled by understanding that, in general, rates and patterns of prokaryotic evolution reflect the developmental history of the Earth's surface environments. Our understanding of modern microbial ecology provides a lens through which our accumulating knowledge of physiology, molecular phylogeny and the Earth's history can be integrated and focussed on the phenomenon of prokaryotic evolution.

The mouthparts and associated structures and the feeding mechanism of two small atyid prawns, Caridina africana and C. nilotica, are described in detail. Both species collect fine particles of food with the chelipeds, which for this purpose are armed with greatly modified spines and setæ, and transfer them rapidly to the mouthparts. Here the food is removed from the chelipeds by a grid-like arrangement of setse on the first maxillipeds and combed from these by the highly modified and teasel-like distal portions of the maxillæ which operate in conjunction with the first maxillipeds as a single functional unit. From these it is passed to the maxillules and thence to the mandibles.

An attempt is made to reconstruct on a functional basis the route by which primitive malacostracans could reach the condition now found in Caridina, and the evolution of chelipeds is discussed.

Granites and their associated comagmatic felsic volcanic rocks occur in most Proterozoic provinces of Australia. Using multi-element, primordial-mantle-normalised abundance diagrams and various petrological characteristics, Australian Proterozoic granites can be subdivided into five groups: (i) I-type, Sr-depleted, Y-undepleted, restite-dominated, (ii) I- type, Sr-depleted, Y-undepleted, fractionated, low in incompatible elements, (iii) I-type Sr-depleted, Y-undepleted, enriched in incompatible elements (anorogenic granites), (iv) I-type, Sr-undepleted, Y-depleted, (v) S-type, Sr-depleted, Y-undepleted. The four Sr-depleted groups dominate, and group (iv) is of very limited extent. A comparison of these Proterozoic granites with Australian and Papua New Guinean granites of other time periods shows that these characteristic Sr-depleted Y-undepleted patterns are also dominant in early Palaeozoic granites. They are significantly different from those of granites in modern island arcs associated with subduction, and with most granites from Archaean terranes, where the multi-element diagrams are dominated by Sr-undepleted, Y-depleted patterns.

The Sr-depleted, Y-undepleted patterns are thought to indicate source regions that contained plagioclase but not garnet, whilst the Sr-undepleted, Y-depleted patterns are taken to correspond with the presence of garnet, but not plagioclase, in the source rocks. The Sr-depleted, Y-undepleted patterns also only occur in regions where the lower crustal structure is dominated by an underplated mafic layer with a P-wave velocity of 7·2-7·-4 km/s. In contrast, in regions where the granites are dominated by Sr-undepleted, Y-depleted patterns, such as in the Archaean and in Cainozoic island arcs, this intermediate velocity layer is not present, and the crust-mantle boundary is very sharp.

Two other distinctive compositional changes have been noted among the I-type granites of different age. Firstly, Na is highest in Archaean and Cainozoic granites, and lowest in early Proterozoic granites; Palaeozoic and Mesozoic granites have intermediate values. Secondly, late Archaean and Proterozoic granites are the most enriched in K, Th and U, while the Cainozoic and early Archaean tonalites are the most depleted; Palaeozoic and Mesozoic granites again contain intermediate amounts of those elements.

The arid climate of the Altiplano has preserved a volcanic history of ∼11 million years at the Aucanquilcha Volcanic Cluster (AVC), northern Chile, which is built on thick continental crust. The AVC has a systematic temporal, spatial, compositional and mineralogical development shared by other long-lived volcanic complexes, indicating a common pattern in continental magmatism with implications for the development of underlying plutonic complexes, that in turn create batholiths.

The AVC is a ∼700-km2, Tertiary to Recent cluster of at least 19 volcanoes that have erupted andesite and dacite lavas (∼55 to 68 wt.% SiO2) and a small ash-flow tuff, totalling 327 ± 20 km3. Forty 40Ar/39Ar ages for the AVC range from 10·97 ± 0·35 to 0·24 ± 0·05 Ma and define three major 1·5 to 3 million-year pulses of volcanism followed by the present pulse expressed as Volcán Aucanquilcha. The first stage of activity (∼11–8 Ma, Alconcha Group) produced seven volcanoes and the 2-km3 Ujina ignimbrite and is a crudely bimodal suite of pyroxene andesite and dacite. After a possible two million year hiatus, the second stage of volcanism (∼6–4 Ma, Gordo Group) produced at least five volcanoes ranging from pyroxene andesite to dacite. The third stage (∼4–2 Ma, Polan Group) represents a voluminous pulse of activity, with eruption of at least another five volcanoes, broadly distributed in the centre of the AVC, and composed dominantly of biotite amphibole dacite; andesites at this stage occur as magmatic inclusions. The most recent activity (1 Ma to recent) is in the centre of the AVC at Volcán Aucanquilcha, a potentially active composite volcano made of biotite-amphibole dacite with andesite and dacite magmatic inclusions.

These successive eruptive groups describe (1) a spatial pattern of volcanism from peripheral to central, (2) a corresponding change from compositionally diverse andesite-dacite volcanism to compositionally increasingly restricted and increasingly silicic dacite, (3) a change from early anhydrous mafic silicate assemblages (pyroxene dominant) to later biotite amphibole dacite, (4) an abrupt increase in eruption rate; and (5) the onset of pervasive hydrothermal alteration.

The evolutionary succession of the 327-km3 AVC is similar to other long-lived intermediate volcanic complexes of very different volumes, e.g., eastern Nevada (thousands of km3, Gans et al. 1989; Grunder 1995), Yanacocha, Perú (tens of km3, Longo 2005), and the San Juan Volcanic System (tens of thousands of km3, Lipman 2007) and finds an analogue in the 10-m. y. history and incremental growth of the Cretaceous Tuolumne Intrusive Suite (Coleman et al. 2004; Glazner et al. 2004). The present authors interpret the AVC to reflect episodic sampling of the protracted and fitful development of an integrated and silicic middle to upper crustal magma reservoir over a period of at least 11 million years.

An analysis of the structural style of the Palæozoic rocks exposed around Girvan in S.W. Ayrshire suggests that it was fashioned by at least nine phases of deformation. Five of these phases were active when maximum pressures were horizontal and together constitute the local expression of the Caledonian orogeny. The oldest phase recognized, the Main fold phase, consisted of overfolding due to an over-riding maximum pressure from between 150° and 170° and was penecontemporaneous with thrusting generated by a modal maximum stress from 145° to 325°. Three important thrust belts resulted but there were considerable local swings in the azimuths of maximum stress, a variation which culminated in the propagation of the Ardwell fold and reverse fault phase by a maximum stress from 110°. Later Caledonian movements, presumably influenced by an increase in overburden due to folding and thrusting, were represented by two episodes of wrench faulting: an older Ardwell “cross-fold” phase due to a maximum stress from north-east to south-west and a younger Main wrench system with a maximum stress aligned at 160–340° which generated an intricate pattern of sinistral and dextral shears together with second-order relatives. The three following phases, the first, second and third “normal” phases represented an episode in stress history when the relief of pressure was horizontal and aligned from approximately north to south, north-north-west to south-south-east and just north of west to south of east respectively. Maximum pressures tended to vacillate between the vertical and near horizontal and as a result much of the faulting was oblique-slip. All three phases were responsible for important faults and some evidence is put forward to suggest that all three are possibly Proto-Armorican or probably not later than Armorican, although the existence of a few mineral veins shows that reactivation certainly took place in Borcovician times. An analysis of the tensional joints recorded for the area indicates that, apart from the dominant Caledonian and less conspicuous Armorican sets, Tertiary joints were formed when there was a relief of pressure from north-east to south-west and this final phase of deformation was accompanied by the intrusion of dykes.

The study also includes discussions on the methods and merits of the resolution by stereographic means of the stress fields responsible for oblique-slip faults and on the nature and origin of first- and second-order wrench faulting in the light of the abundant statistical data available.

The dust particles floating in our atmosphere are every day demanding more and more attention. As our knowledge of these unseen particles increases, our interest deepens, and I might almost say gives place to anxiety, when we realise the vast importance these dust particles have on life, whether it be those inorganic ones so small as to be beyond the powers of the microscope, or those larger organic ones which float unseen through our atmosphere, and which, though invisible, are yet the messengers of sickness and of death to many—messengers far more real and certain than poet or painter has ever conceived.

The object of this research was to compare the feeding mechanism of Nebalia with that of Hemimysis described by Miss Manton and myself (1927). The observations of the living animals were made partly at Naples while I was occupying the Cambridge University table, and partly at Plymouth where I had the use of the London University table.

The methods used in determining the feeding currents were the same as those used for Hemimysis (Cannon and Manton, 1927). To obtain a ventral view of the trunk limbs, I simply held the living animal upside down, gripping the abdomen with a pair of forceps, and in this position it would feed for a long time. I found it possible even to remove the entire carapace without killing the animal or upsetting the normal movements of the limbs.