The establishment of Primula petiolaris and its allies as representing a distinct section of the genus was the work of Pax in Engler's Bot. Jahrb., x, 173 (1889). His definition of the section was reasonably adequate, allowance being made for the scanty material available to him. The main information at his disposal came from Wallich's diagnosis (1) of P. petiolaris in 1824 and Hooker's treatment (2) of that species and its varieties in 1882. The chief diagnostic marks instanced by Pax were the membranous leaves with very broad midrib and with sharply and closely erose-denticulate margin, the great variability in leaf-shape and in the degree of development of the scape, the rose-coloured flowers and the globose capsule. Very apposite were his comments on the difficulty in distinguishing the component species and his conviction that the many varieties of P. petiolaris may quite well represent individual species, although the lack of careful observations on living material compelled him to leave within that aggregate even such plants as P. Tanneri. Pax's conception of the confines of his section was better exemplified by his choice of its components than by his diagnosis.

The section Farinosae was first denned by Pax (1) in 1889 with citation of P. farinosa and P. sibirica as representative species. He published at the same time his section Auriculatae. The only distinction given of apparent moment between the two sections is the shape and size of the capsule. In Auriculatae it is globose and included in the calyx, while in Farinosae it is cylindric and more or less exserted. This diagnostic character was found to be unsatisfactory, with the result that in 1905 Pax (2) in his Monograph combined the two sections under Farinosae. There was still an undercurrent of opinion that a division was justified, and at the Third Primula Conference in 1913 Bayley Balfour (3) reverted to the previous arrangement without, however, any stated reasons. At the Fourth Primula Conference held in 1928 the sections of the genus were reviewed by Smith and Forrest (4), who again subordinated Auriculatae to Farinosae. In 1932 appeared Bruun's Cytological Studies in Primula (5), with a detailed analysis of the species then available in cultivation. Here valid evidence was given that certain species assessed in the past as within Auriculatae did differ cytologically from the general run of species included without question in the Farinosae. But the cytological evidence taken alone tends to associate these Auriculatae with other species quite dissimilar from the broad morphological point of view. The problem is referred to again by Wright Smith (6) in his Hooker Lecture, where it is admitted that the cytological data do support the view that there is a degree of fundamental difference between the two sections. But the difficulty still remains of finding satisfactory macroscopic distinctions. The present authors have come to the conclusion that it is better to keep both under the general heading Farinosae rather than to separate them by slender and often misleading characters supported as these may be by the cytology. In any case much remains to be done on the cytological side, as the majority of the species are yet to be analysed, and for general purposes the incorporation of the cytological data in an analytical key would not be satisfactory.

The typical species of this small section and the first to be described is P. cuneifolia. Within its compass are three other plants which in their time have been given specific diagnoses but are here regarded as coming more properly into the category of subspecies—P. saxifragifolia, P. hakusanensis, and P. heterodonta. P. cuneifolia, thus interpreted, has a distribution extending from N.E. Siberia to Japan, the Aleutian Islands, and the Alaskan coast. The section contains two other species—P. nipponica which is confined to Japan, and P. suffrutescens from the Sierra Nevada of California, thus widely separated geographically.

Within recent years several human ova in the previllous stage of development have been discovered and their study, taken in conjunction with the detailed observations of Heuser and Streeter (1941) on the development of the macaque embryo, has resulted in fundamental modifications of the views previously held concerning the early development of the human embryo.

The outlook on early human embryology comprises three phases: first, the phase when only very few specimens had been discovered and the tentative conclusions drawn from their study were to a considerable extent merely surmised by analogy with the phenomena known to occur in the development of other animals; second, the phase where sufficient material has been acquired to enable investigators to verify or deny some of these postulations and even to suspect certain possibilities—like variations in the degree of development of the various elements in embryos of approximately the same age such as is known to occur in other mammals, or early histological changes indicating pathological relations between the embryonic and maternal structures which may foreshadow the failure of continued embryono-maternal relations and impending abortion; and third, a phase when the specimens will be so numerous that the conclusions of the earlier periods can be established with certainty or definitely refuted. At present, early human embryological study is in the second phase, and the early attainment of the third phase is desirable to fill gaps in the present knowledge of the stages in the development of several structures (e.g. the yolk-sac, the amnio-embryonic vesicle, etc.) and to determine details necessary for a more precise comparison of the development of the human ovum with that of other primate and of lower vertebrate forms.

The Archæan rocks of the southernmost part of the parish of Harris in the Outer Hebrides have long been known to include not only a wide variety of gneisses of igneous origin, but also a group of paragneisses which, along with presumably contemporaneous formations in Glenelg, Tiree, Iona and elsewhere, probably represent the most ancient sediments in Britain. Apart from early references by Macculloch (1819) and Heddle (1878, 1888, 1901), for practically all our present information on these gneisses we are indebted to Jehu and Craig (1927), who have made a reconnaissance survey over the whole chain of the Outer Hebrides and whose work forms the standard account of the geology of this region.

The present paper gives a description of the gneisses around the village of Rodil, a district of somewhat complex petrography and metamorphic history. The paragneisses present include crystalline limestones, calc-silicate rocks, garnet-kyanite-gneisses, graphite-schists, quartzites, and other schistose and gneissose rocks less easily described by short titles. These sediments have been intruded by sills or sheets of basic to ultrabasic composition, now represented by gneisses of the composition of eclogite, garnet-amphibolite, amphibolite, peridotite, pyroxenite, saxonite, websterite, and a series of rocks referred to under the portmanteau name of metagabbro—types akin to pyroxene-granulites and basic charnockites, often garnet-bearing, but locally with pyroxene and garnet replaced to a varying extent by hornblende and biotite. There is also present a large mass of anorthosite-gneiss bordered by metagabbros, both the feldspathic and basic rocks bearing frequent schlieren of eclogite, garnet-amphibolite, and amphibolite. The complex is traversed locally by acid and basic pegmatite dykes and sheets.

A series of extensive temporary exposures in glacial deposits, partially filling an abandoned valley of the River Dee immediately south of Torry Hill, Aberdeen, has thrown some light on the late glacial history of the Aberdeenshire coastal strip. These deposits consist of rather more than twenty feet of fine, well-stratified sediments, similar to sediments recorded in other parts of the city of Aberdeen, and at a number of points along the coast almost as far as Peterhead.

These sediments, which were first mentioned by T. F. Jamieson (1858), were not differentiated by him from the red boulder clay found also in this area. A. Bremner (1915), the only worker to publish important communications on the glaciology of the area since Jamieson, has explained the sediments as deposits formed in glacial lakes when an ice-sheet filling the North Sea dammed the natural drainage. Bremner (1931) believed that three separate ice sheets had succeeded one another in North-East Scotland. The ice sheet responsible for damming up the waters in which the sediments under discussion were formed was the second of these. It moved in a northerly direction in this area, bringing with it erratics from the Old Red Sandstone of Strathmore. The third ice sheet was local. Movement was eastwards from the high ground towards the sea. According to Bremner, this ice failed to reach the coast at some points, as, for instance, immediately south of the Bay of Nigg. However, in the area of Aberdeen city this ice is supposed to have given rise to the morainic topography which backs the beach.

Previous studies on the cytology of the wild and less highly developed “diploid” forms of potatoes have been mainly concerned with the number of chromosomes. Rybin (1933) in his cytological investigation on the South American cultivated and wild potatoes has recorded 12 as the haploid number of chromosomes in seven species including S. Rybinii. Ratera (1938) reported the same number of haploid chromosomes in S. Parodii and six other species indigenous to Argentine.

The present study is concerned primarily with the secondary pairing of chromosomes at meiosis in six “diploid” species with a view to determining the basic number in potatoes and to ascertaining the exact “status” of these species.

It has been known from antiquity that involution of the uterus is aided by putting the child to the breast, and the work of Moir (1933) has demonstrated conclusively that suckling brings about waves of contraction of the puerperal uterus. Since suckling must necessarily involve stimulation of the nipple, it seemed of interest to know what sensory apparatus is present in the nipple to receive these stimuli. While histological studies of the mammary gland itself have been numerous, only slight attention has been paid to the histological structure of the areola and the nipple.

It must be appreciated from the outset that the present study is devoted to the innervation of the nipple in the quiescent breast. There may be considerable change during pregnancy and lactation, not only in the size of the organ and its epithelium but also in the other structures. It has been shown that there is an increase in the number of nerve-fibres in the actively secreting mammary tissue, and it is possible that there is an increase in the nerve-structures of the nipple also. The richness of the innervation in the quiescent nipple certainly makes a further study of these nerve-structures during pregnancy and lactation of great interest.

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

The Clyde Plateau Lavas which are part of the Lower Carboniferous succession in the west of Scotland form the main mass of the Campsie Hills in Stirlingshire and the Kilpatrick Hills in Dunbartonshire. Below the lavas at the western end of the Campsie Hills are cement-stones and sandstones of the Ballagan Series. These are the lowest beds of the Carboniferous in this area, and in places are seen to overlie without apparent unconformity the Upper Old Red Sandstone. Few fossils have been found in them; the only plants so far recorded are Asterocalamites scrobiculatus Schloth. sp. and Alcicornopteris convoluta Kidst. (Walton, Weir and Leitch, 1938, p. 1345). All that may be said with certainty is that these beds are part of the Calciferous Sandstone Series and are probably the equivalent of the Cement-stone Group. In the Edinburgh area Alcicornopteris convoluta has been found at the base of the Cement-stone Group in beds which lie conformably on the Upper Old Red Sandstone. In the Kilpatrick Hills there are sandstones, shales and thin coal seams below the lavas in Glenarbuck and near the Loch Humphrey Burn. From the latter locality Scott (1924, p. 569) has recorded Calamopitys radiata Scott, C. zonata Kidston, Bilignea solida Kidst. and B. resinosa Scott, which were found in coarse volcanic ash.

The existence in Mexico of blight-resistant species of potato has been known for many years, but they occur in the wild and are quite unsuitable for agricultural purposes. In order to utilise their resistance to disease it is necessary to combine disease resistance with the cropping qualities of cultivated forms while eliminating the undesirable characters which are prominent in the wild forms. Breeding work with this object in view has been in progress at the Scottish Plant Breeding Station for several years, and results obtained in the course of testing progenies for reaction to blight infection are discussed in the following pages.

Fossils have been known to occur in the early “post-Caledonian” sediments of Cowie Harbour, Stonehaven, for more than sixty years. Dr R. Campbell (1911, 1912 a, b, 1913) gave an account of the stratigraphy and recorded a number of fossils, including plant-fragments, arthropods (subsequently discussed by Steamer, 1934, 1935), and fishes (Traquair, 1912; Kiaer and Heintz, 1932 a; Heintz, 1939). The fossinferous “Dictyocaris-band,” exposed on the tidal foreshore, has been visited repeatedly by members of this department, who have collected a considerable quantity of fragmentary remains. During the last few years interesting new forms have been obtained by Dr F. H. Stewart, by the writer, and by senior and research students. Faunal lists and a discussion of the age of the beds occur later in this paper. The Dictyocaris-band outcrops also in the Tewel Burn. A cephalaspid scale from this section (Geol. Surv. Scot., T. 2738c and T. 2739c) is described below.

Soils developed on basic igneous rocks, or their associated glacial drifts, are of fairly common occurrence in North-East Scotland and occupy a considerable area in Aberdeenshire. So far, only isolated studies with some specific object in view have been made of such soils, and a few descriptions with analyses have been published (Mitchell, 1936; Muir and Fraser, 1940; Whelan, 1939; Ogg, 1935). Interesting and important facts have been brought out in these investigations, but, apart from the work of Muir, no attempt has been made to study the distribution and field relations of the soils, and arable soils are mentioned only incidentally by Muir. In the present study an account is given of the classification and distribution of the various soil types occurring in the Kennethmont, Insch, Old Meldrum district of Aberdeenshire, an area which is highly farmed and which has long had a high reputation for its fertility and productivity. A soil map is given at the end of this study.

Among the numerous fragments of plants found inside the fossil hollow tree stumps of Lepidophloios wünschianus Carr. from the Calciferous Sandstone Series in the island of Arran (Walton, 1935, p. 313) are two small portions of a strobilus. These fragments are embedded in the calcite matrix, and as they are separated from one another by a distance of only a few millimetres it is possible that they are parts of one strobilus. They have suffered considerable maceration and distortion before petrification occurred. A series of over 54 peel sections transverse to the axes of the two fragments and a series of 80 longitudinal sections through one of them were prepared. The longitudinal sections were made from 4 mm. of the block of material. Each section therefore used on an average 0·05 mm. of the block.

The Western or Toro-Ankole volcanic province of Uganda consists of several areas of tuffs, explosion craters, and rare lava flows situated to the east and south-east of Ruwenzori (text-fig. 1). From north to south these volcanic fields are distinguished under the names (a) Rusekere; (b) Fort Portal; (c) Ndale, formerly known as the “Kyatwa area”; (d) Katwe-Kikorongo; (e) Bunyaruguru, formerly known as the “Kichwamba area”; and (f) Katunga. The Bunyaruguru field extends southwards from Lake George in and adjacent to the north-eastern portion of the Lake Edward section of the western rift. The Kabirenge and Lyakauli lavas (text-fig. 2) occur on the eastern edge of the rift depression immediately north-west of Nyondo crater (E. 30° 04′ 25″; S. 0° 14′ 30″). As a group, they constitute one of the four lava occurrences now known in Bunyaruguru, the other three being those of Chamengo, Mafuru, and Kazimiro (text-fig. 2). Otherwise, lava occurs only as fragments and lumps in the tuffs and as bombs and ejected blocks. The Kabirenge-Lyakauli lavas are also of special interest because, as described later by Professor Holmes, they consist of various members of the mafurite series, characterised by the presence of the recently discovered mineral kalsilite, a polymorph of KAlSiO4.

Studies of the growth stages of some species of Promicroceras (Currie, 1942 and 1943) have led to similar inquiries into the growth stages of other genera. The choice of genera studied has been determined mainly by the material available; but fortunately the material available has provided an opportunity for investigation of a compressed fairly involute form (Witchellia) and some depressed involute forms (Cadoceras and some Sphaeroceratids) for comparison with the evolute Promicroceras.

Most of the specimens used are from a collection of ammonites kept for study by Professor A. E. Trueman, to whom the writer is again indebted for material. Other specimens used are from the collection of the Hunterian Museum, Glasgow University. As usually happens in investigations of this kind, a number of the specimens cut had to be discarded owing to the structure being obliterated by calcification. As a result, the number of measurable sections available was smaller than one had hoped.

Within the last twenty years our knowledge of the structure and distribution of the armoured Placodermi (including Arthrodira, Ptyctodonta, Phyllolepida, Macropetalichthyida, Rhenanida, and Antiarcha) has increased tremendously. The writer is engaged on a morphogenetic analysis of the group, early publication of which is uncertain. A recent paper by Gross (1941) deals among other matters with the nature of the Antiarch pectoral limbs, and since my own conclusions partly support and partly oppose his very interesting hypothesis, it seems desirable to discuss separately the nature and possible evolution and morphogenesis of these unique vertebrate appendages. To do so it is necessary to review the paired limbs of other placoderms and of Acanthodii, with special reference to their functional significance.

Although there have been many accounts of the anatomy, and a small number of the function of the stomach of a variety of molluscs, there has been little or no comparative study of an organ which recent work has shown to be largely responsible for the simultaneous performance of a large number of different components of the entire physiology of the digestive tract. To make such a comparative account on the basis of previously published descriptions would, in fact, have proved an impossible task, as it has become apparent during the course of this work that adequate emphasis has never been laid upon the minutiæ of gastric structure or function, and it is upon these that a correct comparative interpretation must rest.

The present paper records an investigation into a new and unusual suctorian, found epizoic on the cuticle of the Cirripede, Conchoderma aurita. The Cirripede host was obtained from a Blue Whale (Balaenoptera musculus), in the S. Pacific. The collection was made at the Whaling Factory Ship Southern Empress, by the Whaling Inspector, Commander H. Buckle, and the material was then sent to Britain with the collections of H.M.R.S. Discovery. The new form, Metephelota coronata, was first discovered by Professor H. Graham Cannon in the course of an anatomical study on Conchoderma. Recognising that M. coronata might be a new member of the Ephelotidæ (Collin, 1912), Professor Cannon, with great kindness, transferred the whole of the available material to me for further study. This has shown that the material consists of a single new species, generically distinct from Ephelota and Podocyathus, the two previously known genera of the Ephelotidæ.

The volcanic rocks of Iceland have been grouped by Tyrrell and Peacock (1928) into:

3. The Recent, Post-Glacial and Late Interglacial Eruptives.

2. The Early Glacial Breccia or Palagonite Formation.

1. The Pre-Glacial Kainozoic Basalt Plateau.

Group 1 consists of nearly 10,000 feet of basalts with lignite beds, acid extrusives and acid and basic intrusions. In the east and west of Iceland the old plateau is exposed, but centrally it is down-faulted and covered with more recent tuffs and lavas.

Group 2 contains a varied assemblage of deposits comprising tuffs, breccias and lavas, moraines, boulder clays and fluvioglacial sediments (Nielsen and Noe-Nygaard, 1936 a). The lower part of this formation consists of over 2000 feet of basaltic lavas with interbedded glacial and fossiliferous deposits, and the upper part of glacial and fluvio-glacial deposits with doleritic lavas.

Group 3 is made up mainly of basaltic lavas but with occasional acid phases. In the ice-covered highlands the volcanoes have continued to produce tuffs and breccias.