The nominal species Mosasaurus ivoensis from the latest early Campanian of the Kristianstad Basin in southern Sweden, is redescribed and assigned to the tylosaurine genus Tylosaurus on the basis of its dental and vertebral morphology. A partial skeleton (KUVP 1024) from the late Coniacian to earliest Campanian Smoky Hill Chalk Member of the Niobrara Formation in western Kansas, USA, was previously referred to “M”. ivoensis. Nevertheless, its marginal teeth are markedly different, both in size and morphology, from those of topotypic T. ivoensis.

Examination of type specimens and topotypic material of the nominal tylosaurines Hainosaurus pembinensis from the late early Campanian of Manitoba, Canada, H. gaudryi from the late Santonian or early Campanian of northwestern France, and H. lonzeensis from the Coniacian or Santonian of Belgium, indicates that all three may be Tylosaurus.

The utility of isolated tooth-crowns in mosasaur taxonomy has been hampered by the often poor quality of the published illustrations of these fossils in combination with poor stratigraphic control. All Swedish remains of T. ivoensis, including 172 marginal teeth, 6 pterygoid teeth, several jawbone fragments and 12 vertebrae, were collected from a narrow stratigraphic interval corresponding to the highest biozone in the German eight-fold division of the early Campanian, providing the first good insight into the intraspecific dental variation in a tylosaurine mosasaur.

Preliminary §§ 97–101. Fundamental Principles of General Thermo-dynamics recapitulated.

97. Mechanical action may be derived from heat, and heat may be generated by mechanical action, by means of forces either acting between contiguous parts of bodies, or due to electric excitation; but in no other way known, or even conceivable, in the present state of science. Hence Thermo-dynamics falls naturally into two Divisions, of which the subjects are respectively, the relation of heat to the forces acting between contiguous parts of bodies, and the relation of heat to electrical agency. The investigations of the conditions under which thermodynamic effects are produced, in operations of any fluid or fluids, whether gaseous or liquid, or passing from one state to the other, or to or from the solid state, and the establishment of universal relations between the physical properties of all substances in these different states, which have been given in Parts I.-V. of the present series of papers, belong to that first great Division of Thermo-dynamics—to be completed (as is intended for future communications to the Royal Society) by the extension of similar researches to the thermo-elastic properties of solids.

The Devono-Carboniferous chondrichthyan Stethacanthus is best known for its striking 'spine-brush' complex. Here we provide the first detailed description of the neurocranium, using several well-preserved specimens from Bearsden, Scotland (Serpukhovian; Pendleian E1). Significant features include an otico-occipital region of about the same length as the ethmosphenoid division; short but distinct lateral otic processes; a short, broad endolymphatic fossa; a persistent otico-occipital fissure; Y-shaped basicranial canals indicating origin of the lateral aortae anterior to the occipital level; and minimal suborbital shelves limited to small, ethmoidally located outgrowths. Using placoderm, osteichthyan and acanthodian neurocrania for outgroup comparison, PAUP analysis of a matrix of 23 neurocranial characters produced the following branching sequence: (Helodus (Stethacanthus, Cobelodus (Tamiobatis (Xenacanthus (Cladodus wildungensis (Tristychius, Hybodus)))))). The location of Cladoselache in this analysis is uncertain and probably results from missing data and a morphologically restricted character set. Plesiomorphic conditions for chondrichthyan braincases are found to include the presence of a persistent otico-occipital fissure, projection of the median dorsal aorta anterior to the occipital level, and absence of suborbital shelves. These results may have important implications with regard to primitive gnathostome interrelationships, and especially the phylogenetic position of placoderms.

Syenogranites and monzogranites of Edward VII Peninsula, Marie Byrd Land, represent magmatism associated with continental rifting and the separation of New Zealand from W Antarctica in the mid-Cretaceous. These coarse-grained, leucocratic, subsolvus biotite granites occur as five small plutons cutting Lower Palaeozoic metasediments. Petrographic features include the predominance of microcline perthite over albite, bipyramidal smoky quartz, red-brown biotite and accessory ilmenite, zircon, apatite, monazite and fluorite. Enclaves are absent and miarolitic cavites are rare.

The granites are a weakly peraluminous, potassic, and highly fractionated suite with high concentrations of Rb, Nb, Y, HREE and F in the most evolved compositions. REE patterns vary from LREE-enriched (CeN/YbN = 8·4), to flat REE patterns (CeN/YbN = 1·1) with large negative Eu anomalies (Eu/Eu* = 0·02). Initial 87Sr/86Sr ratios are 0·7116-0·7206 and initial εNd values are −5·5 to −7·7. Generalised fractionation trends for the suite are explicable in terms of the modal mineralogy. Monazite crystallisation exerted a predominant control on LREE concentrations.

The geochemistry of the Edward VII Peninsula granites suggests an infracrustal I-type source, and regionally available Devonian-Carboniferous I-type granodiorites and tonalites satisfy the isotopic constraints. The granites classify as A-type (preferred term A-subtype) and Within-Plate Granites on standard diagrams, but the least fractionated rocks clearly indicate the I-type, Volcanic Arc Granite geochemical signatures of their inferred crustal sources.

The first part of this work was published in the Transactions of the Society for 1905, when the present section was promised by the end of the same year. But the labour of revising the whole work on the sections and of posting all the muscles in the extensive series of key sections along with the skeleton has been much greater than was anticipated, and hence the delay. This labour, however, is amply repaid by the knowledge that one is now in a unique position for studying the blood-vessels and nerves; for not only has every fraction of the skeleton and muscles been microscopically explored, but the information obtained is immediately and completely available on reference to the key sections. When the whole work is completed and all the systems have been entered in these sections, I hope to obtain a grant to enable me to publish them as an atlas. As far as I am aware, no animal has been studied throughout in this way before.

Granites within suites share compositional properties that reflect features of their source rocks. Variation within suites results dominantly from crystal fractionation, either of restite crystals entrained from the source, or by the fractional crystallisation of precipitated crystals. At least in the Lachlan Fold Belt, the processes of magma mixing, assimilation or hydrothermal alteration were insignificant in producing the major compositional variations within suites. Fractional crystallisation produced the complete variation in only one significant group of rocks of that area, the relatively high temperature Boggy Plain Supersuite. Modelling of Sr, Ba and Rb variations in the I-type Glenbog and Moruya suites and the S-type Bullenbalong Suite shows that variation within those suites cannot be the result of fractional crystallisation, but can be readily accounted for by restite fractionation. Direct evidence for the dominance of restite fractionation includes the close chemical equivalence of some plutonic and volcanic rocks, the presence of plagioclase cores that were not derived from a mingled mafic component, and the occurrence of older cores in many zircon crystals. In the Lachlan Fold Belt, granite suites typically evolved through a protracted phase of restite fractionation, with a brief episode of fractional crystallisation sometimes evident in the most felsic rocks. Evolution of the S-type Koetong Suite passed at about 69% SiO2 from a stage dominated by restite separation to one of fractional crystallisation. Other suites exist where felsic rocks evolved in the same way, but the more mafic rocks are absent. In terranes in which tonalitic rocks formed at high temperatures are more common, fractional crystallisation would be a more important process than was the case for the Lachlan Fold Belt.

Accurate identification of iron and manganese oxides in soils presents great difficulty because, not only are they always in admixture, but the poor crystallinity of the species present leads to difficulties in interpretation of diffraction patterns. A method involving the combined use of electron microscopy, selected area electron diffraction and electron probe microanalysis on the same crystals gives unambiguous identification. Its application is described in relation to the various iron and manganese oxides found in a set of soils from all parts of the world. The occurrence of hausmannite in soils has been definitely established.

The quartz-sillimanite-garnet rocks of the Precambrian khondalite assemblage of Orissa consist dominantly of SiO2 + Al2O3 + Fe2O3 + FeO (average c. 95%) with Fe2O3 > FeO. An average analysis (H2O and CO2 free) also shows MgO, CaO and Na2O having 1·0, 0·5 and 0·4%, respectively. Compared with average crustal abundances, enrichment is shown in SiO2, Al2O3 and Fetot and depletion shown in MgO, CaO, Na2O and P2O5 with that for CaO being more than an order of magnitude and that for Na2O being a factor of >7. On an SiO2–Al2O3–Fetot plot a clearly defined field, elongate nearly parallel to the SiO2–Al2O3 sideline, is similar to that for deeply weathered soil profiles in Brazil. This correspondence also extends to enrichment, stability or depletion, compared to crustal averages, for Ce, Co, Cu, Ga, La, Ni, Nb, Th, U, Y, Zn and Zr, but not for Ba, Cr and Rb. In addition comparison of the proportions and ratios of alkalis and alkaline earths in average khondalite and in a weathering profile over a granodiorite, considered to be typical of the weathering of continents, shows remarkable similarities.

The major and trace element data are consistent with the khondalites being granulite facies—upper amphibolite facies metamorphic equivalents of a deeply weathered soil profile. Associated quartzites and calc-silicate granulites are interpreted as having been silcretes and calcretes, respectively. This interpretation implies (1) the previous existence of a large stable cratonic mass on which the soil profile formed, (2) climatic conditions suitable for the development of such a profile, (3) topography, drainage systems and groundwater movement in Precambrian times similar to those of present day peneplane regions, (4) the presence of free oxygen in the atmosphere, (5) rapid covering (e.g. by products of volcanism) to preclude mass wasting, (6) a Precambrian stratigraphy in the crystalline rocks of the Eastern Ghats region similar to that of South India, and (7) orogenesis that involved tectonic repetition of lithological units and a mechanism for taking products of surface weathering down to granulite facies P–T conditions and subsequently elevating them.

The description of the postcranial skeleton of larval, metamorphic and early juvenile specimens of the genus Discosauriscus is based on three-dimensional material and includes a description of the ontogeny of the swollen neural arches and the central elements of the vertebrae. Discosauriscus has 24 (or 23) presacral vertebrae. The morphology of the atlas–axis complex is similar to that in Seymouria sanjuanensis. The neural arches start to swell slightly in specimens of late larval stage; they are completely swollen immediately after metamorphosis. There are about 40 caudal vertebrae and one sacral vertebra. The atlantal pleurocentrum is paired in metamorphic individuals. In postmetamorphic individuals, the pleurocentra 2–5 are not completely closed dorsally; the pleurocentra 6–30 form complete discs. The first haemal arch is situated on the sixth caudal vertebra. The atlantal rib is present. There are six caudal ribs. Discosauriscus has an anocleithrum which is the first record of this dermal pectoral element within seymouriamorphs and Lower Permian tetrapods. The scapula and the coracoid are separate elements. The phalangeal formula of the manus is 2, 3, 4, 5, 3. The iliac blade has a massive, almost horizontally oriented posterior process; the anterior process is absent. The phalangeal formula of the pes is 2, 3, 4, 5, 3. Rounded ventral scales are present. The comparison and evaluation of the available postcranial elements of Discosauriscus, Utegenia, Ariekanerpeton and Seymouria support the view that Discosauriscus and Ariekanerpeton, forming the family Discosauriscidae, are immediately related genera.

The early development of the mammary glands and of hair follicles in the mouse and the rabbit has been investigated by means of mitotic counts, by histochemical methods and by cultivation in vitro. In the first stage of the formation of both types of rudiment a thickening of the epidermis appears as a consequence of an aggregation of cells, not of a local elevation of the mitotic rate. During this stage alkaline phosphatase is absent from the cells and the content of ribose-nucleic acid reduced. Both these substances appear in higher concentrations later, and their relation to processes of growth and differentiation is discussed. Essentially similar phenomena are found in rudiments cultivated in vitro, which, however, frequently suffer a degeneration by a process of keratinisation.

The phenomena presented by the prismatic spectra of flames have occupied the attention of many and excellent investigators. In most instances, however, no attempt has been made to procure accurate measurements of the positions of the bright lines which many of the spectra exhibit; and much in this field of observation, therefore, remains to be accomplished. I purpose, from time to time as I shall have leisure, to make a series of observations, whose object shall be the actual numerical determination of the positions of the bright lines in the spectra of flames; and I have commenced the series with an examination of the spectra of the flames of compounds of carbon and hydrogen. In an investigation into the phenomena of flames, the compounds of carbon and hydrogen claim our first attention, as constituting the most important means of artificial illumination; for it is scarcely necessary to remark, that, with the grand exception of sun-light, the combustion of these substances is the source of nearly all the light and heat from which we derive such extensive benefits in the arts and in domestic economy. It will be found, moreover, that the spectra of carbohydrogen flames possess, in common, remarkable features, which seem as yet to have received little attention, but which promise to be of service in explaining the general phenomena of artificial light.

The solid matter floating in our atmosphere is every day becoming of greater and greater interest as we are gradually realising the important part it plays in the economy of nature, whether viewed as to its physical, physiological, or meteorological aspects. One fundamental point on which we have at present very little information of anything like a definite character, is as to the number of solid particles present in our atmosphere. We know that they are very numerous, and it seems probable that the number varies under different conditions of weather; but what number of particles are really present under any conditions, and how the number varies, we have at present very little idea. In this field of research the physiologists are far in advance of the physicists, as they have devised means of counting the number of live germs floating in our atmosphere, and already we have a good deal of information as to how the number varies under different conditions.

Structural features related to habits of life are described for the thermosbænacean Monodella argentarii. Although it can swim, this minute malacostracan is essentially benthic in habits, and its food consists of bottom detritus. The collection and subsequent manipulation of food are described. Monodella is not a filter feeder and no currents are involved in the feeding process which consists essentially of scraping, brushing and pushing. Cephalic appendages only are involved. The structure and mode of action of the mouthparts are described and illustrated in detail, and the functional significance of many structural features is explained.

No justification is found for placing the Thermosbænacea in a separate division, the Pancarida, and its position within the Peracarida is discussed.

The past history and present distribution of the Thermosbænacea are reconsidered.

The modes of life of twenty three species of arthropods from the Shale are reviewed, with special reference to locomotion and feeding. Six groups are recognised, predatory and scavenging benthos, deposit-feeding benthos, scavenging and possibly predatory nektobenthos, deposit-feeding and scavenging nektobenthos, nektonic filter-feeders, and a miscellaneous sixth group that includes a questionable example of parasitism and a species that doubtfully grazed on algae. These animals had but limited powers of walking, digging, raking or swimming. Within these limitations a range of morphological adaptations and modes of feeding had been evolved, by Middle Cambrian time, a range comparable to that found in Recent marine forms. Arthropods in the Shale dominated, in numbers of individuals and possibly in biomass, a fauna dwelling above, on and in a muddy substrate at a depth of about 100 m.

Our knowledge of the primitive and aberrant early tetrapod Crassigyrinus scoticus was based on a partial skull roof and mandibles from the Lower Carboniferous of Gilmerton, Edinburgh, plus a skeleton lacking the hind limb and tail from the Namurian, basal Upper Carboniferous, of Cowdenbeath, Fife. New specimens from Cowdenbeath include the pelvic girdle, presacral and sacral rib and most of the hind limb. The ilium of the girdle had a firm articulation with the vertebral column via the sacral rib. The ischium, separated from the ilium by cartilage, was, like that found with the Cowdenbeath skeleton, ornamented as though a dermal bone. No pubis is preserved. The femur lacks an adductor crest, but has a strongly developed internal trochanter. Tibia and fibula are short stout bones, but axial torsion is present in the fibula rather than the tibia. This, and the structure of the femur, suggests a swimming rather than a walking limb. Probable metatarsals and phalanges are recorded. A skeletal reconstruction and a life restoration of Crassigyrinus are presented in the light of its reconstructed anatomy and physiology.

The ornamentation of the ischium of Crassigyrinus, and that of the colosteid Greererpeton, suggests that the bone may be at least in part dermal. Its homology wth the pelvic fin basal scute of osteolepiform fishes is proposed and the homologies of pectoral and pelvic fins, and thus limbs, discussed.

Zircon is a very interesting accessory mineral, a kind of ‘crustal diamond’, easily recycled and recording through large morphological variability the main rock-forming events. Since 1985, a systematic study of chemical variability of zircon in magmatic rocks has led to the definition of three main generations in zircon populations: inherited phase 1, magmatic phase 2 and late magmatic phase 3. Hafnium and yttrium appear to be the most useful for source characterisation, especially if using phase 2 data. As a consequence, a new diagram of HfO2 versus Y2O3 is proposed, divided into domains la to 6b to describe the distribution of the genetic groups and the specific domains for anorogenic and orogenic rocks. Zircon in anorogenic granitoids: tholeiitic plagiogranites (high Y, low Hf), hypersolvus (medium to low Y, low Hf) and subsolvus (medium to high Y and Hf) alkaline granites/rhyolites, has separate mean distributions. Genetic relations existing between rocks with obvious textural differences (granites, microgranites, rhyolites) are also recognised. Zircon in orogenic granitoids is Y-poor and shows a very limited distribution, but the minimal average values in magmatic zircon vary from 11 000 wt ppm HfO2 in the calc-alkaline suite, to 12 000 ppm in the peraluminous porphyritic granites and to 13 500 ppm in entirely crustal anatectic granites and migmatites. Mixing-mingling processes are proposed to explain the intermediate characteristics of zircons and rocks in the peraluminous porphyritic and K-subalkaline granites. This is consistent with the time emplacement and space distribution of these two orogenic members, but leads to a new proposal of emplacement of some alkaline subsolvus magmas during orogenic cycles.

The Order Adelospondyli, an isolated group of amphibians from the Carboniferous of the Edinburgh area, is redescribed and distinguished from other early tetrapods. Although systematics of genera and species is unsatisfactory, the group seems monophyletic, since as far as they are known, all conform to a single overall structural plan. There is an entire skull roof with a reduced complement of bones in an unique pattern, a highly characteristic marginal dentition, a massive hyoid apparatus, at least 70 holospondylous trunk vertebrae, and (like some other Lower Carboniferous tetrapods) a shoulder region with a heavy dermal girdle but no trace of ossified limbs or endochondral girdle. Adelogyrinids show no special affinity with other Palaeozoic amphibians: the vertebral characters in which they resemble microsaurs, lysorophids, aïstopods, and nectrideans may have evolved more than once among early tetrapods, and the shoulder girdle and neural arch characters shared with labyrinthodonts are probably primitive. The adelogyrinids thus illustrate the more general problems of establishing interrelationships among early tetrapods. Their way of life is discussed.

In analysing Mr Wheatstone's beautiful discovery, that in binocular vision we see all objects of three dimensions by means of two dissimilar pictures on the retina, I trust I have satisfied the Society that the dissimilarity of these two pictures is in no respect the cause of our vivid perception of such objects, but, on the contrary, an unavoidable accompaniment of binocular vision, which renders it less perfect than vision with one eye. On the other hand, it is quite true that, in Mr Wheatstone's experiment of producing the perception of objects of three dimensions by the apparent coalescence of two dissimilar representations of such objects in plano, the dissimilarity of the pictures is necessary in the exhibition of that beautiful phenomenon.

A zircon age of 429 + 6, −5 Ma on felsic volcanic rocks of the Springdale Group, a sequence of bimodal volcanic rocks and redbeds, establishes a Llandovery age for this group. Similar sequences from other parts of the Dunnage and Humber zones of Newfoundland also give Llandovery fossil or radiometric ages, demonstrating temporal correlation among lithologically similar sequences in these zones.

Distinctive sequences of bimodal, subaerial rhyolite and basalt with associated subaerial to shallow marine sedimentary rocks within the Avalon and Meguma zones of Nova Scotia give fossil or radiometric ages demonstrably or arguably very close to the age of the Springdale Group. These sequences suggest an overlap assemblage fixing the minimum age of accretion of the Avalon and Meguma zones to North America. The age and the magmatic and sedimentary character of the assemblage are compatible with origin on or from continental crust, implying that the Iapetus ocean was closed prior to Early Silurian time. If these considerations are correct, the Devonian Acadian orogeny must involve either thermal and mechanical readjustments subsequent to the closing of the Iapetus ocean, or a completely separate episode of plate motion.