XVI. Further observations on the organization of the fossil plants of the coal-measures.—Part II. The roots of Calamites

Until quite recently our knowledge of the roots of the Calamites has been very scanty and limited to such characters as can. be seen with the naked eye, in specimens preserved as casts and impressions. Lindley and Hutton, in 1833, figured a Calamite with two branching roots, inserted immediately above the nodes of the stem in which they were borne, besides other more doubtful specimens of the same kind. Many similar casts have been observed by more recent investigators. Grand’ Eury, for example, has figured numerous specimens of Catamites , bearing roots, both on their rhizomes and their upright stems. So far as his figures show, the roots are always inserted exactly at the nodes.

XI. Experimental researches on vegetable assimilation and respiration.—No. II. On the paths of gaseous exchange between aerial leaves and the atmosphere

That individual cells within the substance of all plants conduct the gaseous exchange necessary for their metabolism by diffusion through their proper cell-walls must be beyond doubt, and that the exchange of gases between a water plant, as a whole, and the surrounding liquid is of the same nature seems as indubitable. When, however, we consider land plants, it becomes less obvious in what way or ways the continuous exchange of gases between the plant and the atmosphere is effected. The epidermis of such plants is covered with a more or less well-developed cuticle, through which specialized openings, stomata, occur with varying distribution and frequency. In maturer parts the epidermis and its cuticle may be replaced by suberised tissue, and the stomata by less specialized openings, the lenticles.

XVIII. An estimate of the degrees of legitimate natality as derived from a table of natality compiled by the author from his observations made at Budapest

Statistics applied to the subject-matter of different sciences are merely a method: but statistics exist also as an independent science, the contents of which represent the demological facts obtained by application of the statistical method. The two branches of demological science, that is, statistics of natality and of mortality, are, both of them, sprung from the soil of England. It was in 1665 that the Royal Society, by publishing the 'Natural and Political Observations,' written by Captain John Graunt three years before, laid the foundation stone of that science which, under the name of Vital Statistics, or Demology (Demography), forms the scientific nucleus of statistical researches.

XII. On the ascent of sap

Many theories have been formed to account for the ascent of sap in high trees, when root pressure is not acting. All have been found, on careful examination, unsatisfactory. Our attention was particularly directed to the problem as we were together in Bonn, in the Summer of 1893, when Professor E. Strasburger was kind enough to show us some of his experiments on the question, and since then we have, at intervals, occupied ourselves with some considerations as to the cause of the ascent of liquids in trees. It was not, however, till late last Spring that we had leisure to enter definitely on the research. We wish to acknowledge the kindness of Professor E. Perceval Wright in giving us the benefit of his advice on all occasions, and also the advantage we derived from Professor G. F. FitzGerald’s suggestive ideas.

III. Researches on the structure, organization, and classification of the fossil reptilia.—Part IX., section 6. Associated remains of two small skeletons from Klipfontein, Fraserburg

In 1888, in the ‘Phil. Trans,' B, vol. 179, I described some parts of the skeleton of Theriodesmus phylarchus . Its geological horizon was then unknown. In the following year I visited the locality where it was found, at Klipfontein, near Fraserburg, in Cape Colony, on the summit of the volcanic series of rocks the escarpment of which forms the Neiuwveldt range. As the base of the Karroo rocks at Prince Albert is fully sixty miles south, and the same strata dip towards the north, over all that distance, with some minor undulations in the southern part of the area, while the elevation of the surface of the country augments northward, Klipfontein holds a high position in the deposits of Permian age which are comprised in the Karroo formation. I had the advantage of the company of the late Mr. Thomas Bain, who conducted me to the farm of two brothers, E. and O. Erasmus, where the Theriodesmus was collected. But after an interval of more than twelve years, the effects of atmospheric forces in breaking and removing the surface rocks made it impossible to discover additional remains of that animal. We carefully explored the banks and bed of a dried stream which drains into the Orange River, where I met with fragments of two species of the ganoid fish, Atherstonia , which have been regarded by Mr. A. Smith Woodward as new species, but found nothing resembling Theriodesmus . Along that stream I found and collected fragments of two skeletons which appear to me to be referable to Theriodonts, though their position in the group is not certain. These fossils show the association of limb bones and vertebrae; and with them I found fragments of skulls, which may have belonged to the same animals; but the association should be made with caution, since it is unsafe to put together disconnected fragments of skeletons which may have been associated by transport, unless there is corroborative evidence that they belong to the same type of organization. These small animals in the character of the humerus are Marsupial in type. This character being associated with carnivorous dentition among existing animals, led me to anticipate the discovery of a skull showing canine teeth. Such dentition though poorly preserved, I found near by, in the bed of the river, associated with the back of the skull.

VII. On the cœlomic fluid of lumbricus terrestris in reference to a protective mechanism

Since the publication of Claparède’s classical memoir on the earthworm, numerous writers have contributed to advance our knowledge of the morphology of this animal. In England, the writings of Ray Lankester, W. B. Benham, and F. E. Beddard have considerably increased the literature of the subject; but, with the exception of incidental references to function, the papers hitherto published have dealt chiefly with the morphology, taxonomy, or geographical distribution of the animal. Darwin long ago collected the observations of Claparède and other older authorities on the physiology of the earthworm, in his work on Vegetable Mould, which consists mainly of his own observations on the habits of the animal. An article “On the Retractile Cilia in the Intestine of Lumbricus terrestris ,” by M. Greenwood, in the ‘Journal of Physiology,’ vol. 13, is, I think, the only systematic contribution in English to our knowledge of the physiology of the earthworm in recent years. The present communication contains the results of an investigation into the functions of the cœlomic fluid. The greater part of the research consists, therefore, of a detailed study of the morphology and physiology of the amœboid cells, which form the most important contents of the cœlom. But in the course of my observa­tions, I was led to investigate some of the chemical characters of the cœlomic fluid, and also to examine certain other structures, such as the skin and the dorsal pores, which form, with the cœlomic fluid, a very remarkable protective mechanism.

VIII. Contributions to the life-history of the foraminifera

In the preface to his classical work, ‘Über den Organismus der Polythalamien,’ published in 1854, Max Schultze acknowledged with regret the incompleteness of the account which he was able to give of the reproductive processes of the Foraminifera. and pointed out that a rich field here lay open for future investigation. In the years that followed Schultze him self made further contributions to our knowledge on this head, but, important as they were, they only went a short way towards solving the problem.

IV. On the evolution of the vertebral column of fishes

The importance of the problems attempted in the present communication needs no special comment, but I have much pleasure in expressing my thanks to generous friends for kind assistance. Mr. Adam Sedgwick put at my disposal his probably unique and comprehensive collection of well-preserved embryos and prepared slides, illustrative of the development of Scyllium, Acanthias , and Acipenser .

XIII. The effect of environment on the development of echinoderm larvœ: an experimental inquiry into the causes of variation

The influence of external conditions upon the growth and development of plants and animals has been known for a very long time, and has been made the subject of careful observation by many horticulturists and breeders, in addition to those who have attacked the problem in a more scientific spirit. As a rule, the changed conditions of environment, of which the effects were to be observed, were very considerable, and not such as might occur in nature, and the effects produced were not generally subjected to exact measurement. It seemed of interest, therefore, to determine as exactly as possible by measurement the effects which such slight changes in environment, as might occur under natural conditions, would produce in the growth of some organism, with a view to ascertaining how far the variations in size and relation of parts which occur in all animals may be caused by these external conditions, apart from such variations which arise from intrinsic differences in the germ. The animal chosen lor this purpose was the larva or pluteus of the sea-urchin, StroJigylocentrotus lividus. These larvae have the merit of being very hardy, and they develop readily from artificial fertilisations without any special precautions being taken. Moreover, it was found that these artificial fertilisations could be effected at all times of the year, irrespective of season. The chief objection to the choice of this animal lies in the fact that the growth of the larvae cannot be carried to the adult stage, so that it is only possible to measure the effect of environment at a particular period in their development. The plan of operations was very simple. About six or eight sea-urchins, which, as a rule, had been freshly obtained the same morning, were cut open, and pieces of the ovaries of each of the three or four female specimens shaken with forceps in a small jar of sea-water. Pieces of the testes were shaken in another jar, and the contents of the two jars mixed and stirred, the temperature being meanwhile noted. After standing an hour portions of this water containing the artificially fertilised ova were poured into glass jars containing 2 to 31/2 litres of sea-water. These jars were then transferred to a large glass tank, through which a stream of sea-water circulated, and were allowed to remain there throughout the whole period of development. Evaporation was prevented by covering the jars with glass lids. As a rule, the development was allowed to proceed for eight days, as the arms of the plutei attain their maximum development by the end of this time. A volume of saturated corrosive sublimate solution was then poured in each jar, such that the water should contain about '25 per cent, of it. In a few minutes all the larvae had sunk to the bottom. The supernatant liquid was poured off, and the larvae with 100 or 200 cub. centims. of water transferred to a small beaker, from which more of the liquid was poured off. The larvae were then washed in distilled water, and then in 50 percent, alcohol. They were finally transferred to, and preserved in, 70 percent, alcohol, to measure the larvae, they were washed on the slide in water, and mounted in glycerine. Several hundred, in positions suitable for measurement, could be obtained on a single slide. The larvae were measured under the microscope with a micrometer eyepiece, Zeiss, Obj. CC. Ocular, No. 3, The position of each larva measured was observed on the mechanical stage, and noted, so that it could not by mistake be measured twice. Three measurements were made, namely, the body length AB, the aboral arm length AC, and the oral arm length AD. The length of the calcareous skeleton in the body and limbs was always measured, in preference to the soft tissues surrounding it, as it is sharply defined, and therefore more suitable for the purpose. If is moreover of practically the same length as the soft tissues. In Fig. 1 are shown the measurements made. Only larvae in the position indicated in this figure were measured, as with larvae in the position indicated in Fig. 2, the oral arm is foreshortened.

XVII. Further observations on the organization of the fossil plants of the coal-measures.-Part III. Lyg.nodendron and heterangium

The two genera, Lyginodendron and Heterangium , are among the most interesting, and at the same time the most puzzling, representatives of the Carboniferous Flora. Although, unfortunately, we are still without any satisfactory evidence as to the nature of the reproductive organs in either genus, yet the structure of all their vegetative parts is preserved with such completeness and perfection as to enable us to show, that these fossils present a combination of characters such as exists in no group of plants now living. So long as the mode of reproduction is unknown, it will remain impossible to assign these genera definitively to their systematic position; in the mean time, we can only weigh with due care such evidence as is afforded by their vegetative structure. This evidence, as we shall show, clearly indicates, so far as it goes, a position intermediate between Ferns and Cycads.