The following account of the anatomy of the head of a fœtal African Elephant was made possible by the acquisition of a single specimen, preserved immediately after extraction from the mother, who was shot in the Belgian Congo. As far as is known, this fœtus is the only well-preserved specimen in existence, the total number of fœtuses recorded since 1734 being twelve.

Apart from the skeleton, our knowledge of the anatomy of present-day Proboscideans is very meagre. The dissection hitherto carried out has been either a hasty study of the complete adult carcase, or a more lengthy observation of preserved portions of the animals. Both methods lead to inaccuracy, and provide an explanation of the numerous discrepancies in the accounts. When, therefore, the present Congo foetus was acquired by purchase from the Belgians who preserved it, and Professor D. M. S. WATSON kindly allowed me to have it for dissection, I determined to make the fullest possible use of this unique specimen. The dissection of the head was carried out under the Zeiss Binocular Dissecting Microscope, and sketches and photographs were prepared at intervals, so that every record should be kept.

The exact horizon occupied by the Shetland strata of Old Red Sandstone age, and their relation to the corresponding series in the north of Scotland, have long been subjects of considerable speculation and much uncertainty. While their resemblance to the flag-stones of Caithness and Orkney was generally recognised, more definite palæontological evidence was required for correlation purposes, and the barrenness of the islands in this respect has been commented on again and again. Up to quite recent years the only fossils found in Shetland were fragmentary plant remains of doubtful affinities, and the small crustacean Estheria membranacea; the abundant ichthyolites which characterise the beds of Caithness and Orkney seemed here to be wanting, and the dearth of fossil evidence is reflected in the conservative and guarded opinions as to the position to be assigned to the series.

Hitherto in matters craniological the student has been confronted with the primary difficulty that the series upon which he intends to work has been unearthed many years after burial. In consequence the question of age, sex, and nationality has remained a matter of doubt. In the present series of Hokien and Tamil skulls this difficulty has been entirely eliminated. As the skulls were collected immediately after death, the age, sex, and nationality of each is known. On removal from the body each skull had a metal tally attached to it, so that no error could arise in the process of preparation. In craniological and craniometrical work one frequently meets with the term “Chinese,” and the author is uncertain of the probable locality from which the skulls were obtained. China covers a vast expanse much larger than most people realise, and its inhabitants include a large variety of branches which vary widely in craniological features. Even in language and religion they differ, and it frequently happens that individuals living 100 miles from one another cannot understand each other's spoken language, although the written characters are identical. In fact the Hokiens call the Northern Chinese “foreigners.” The dissimilarity between the Cantonese Chinese and the Hylam Chinese skull is, I believe, as great as that between the Scottish and the German skull.

This research was undertaken as an endeavour to build up a method of discrimination of magnetic lattices in crystalline substances. Theory, due to Professor Peddie, hereafter referred to and expanded in detail, gives an estimate of the intensity of Magnetisation in a co-directed system of regularly arranged magnetic doublets, such as we may regard a magnetised piece of crystalline substance to be composed of.

When a magnetic field is applied to a crystalline portion of matter it is magnetised, not necessarily in the direction of the field, as would be the case if the substance were purely amorphous, but in general in some direction inclined to that of the magnetising field. This is due to the crystalline quality of the body, and the consequent internal inter-polar magnetic reactions. The saturation intensity of magnetisation in any plane is constant, but its obliquity to the field varies with the orientation of the field in the substance. The external field is assumed to be strong enough to co-direct all the molecular magnets; that is, to produce saturation.

Because of the superficial resemblance of the digestive diverticula of the Lamellibranchs, and of many other Invertebrates, to the liver of the Vertebrates, and the discovery in them of glycogen by Bernard (1855), they became known as the “liver.” Weber (1880) later introduced the name hepatopancreas as a result of his discovery of the secretory powers of the diverticula in the Crustacea. In spite of the fact that none of the constituents of bile has ever been discovered in the Invertebrates, and that the digestive diverticula are in no way analogous to the liver of the Vertebrates, as Jordan (1912) has shown in his review of the subject, the terms “liver” and “hepatopancreas,” as well as the less questionable designation “digestive gland,” are still generally used. Moreover, no attempt is made to distinguish between these organs in the different groups of Invertebrates although both their structure and function in, for example, the Lamellibranchs, Gastropods, Cephalopods, and Crustacea are totally different. In some cases they constitute a digestive gland; in others, including the Lamellibranchs, as I hope to show in this paper, their function is that of assimilation, and so they are most suitably designated digestive diverticula.

The cranial structures of Protopterus and Lepidosiren are now fairly well known, and especially owing to the investigations of Bischoff, Bridge, Fürbringer, Göppert, Humphry, Hyrtl, Jaquet, Luther, Maurer, Owen, Pinkus, Ruge, and Wiedersheim, on their adult anatomy, and to those of Kerr and Agar on their development.

Some papers on the development of Ceratodus, which I have recently published, suggested the advisability of obtaining further information on certain points, and this became possible owing to the generosity of Professor Graham Kerr, who gave me both larval and adult stages for the purpose.

The richness of the Ordovician and Silurian rocks of Girvan in organic remains has long been known, and during recent years many of the fossils have been described by various authors. But occasionally fresh material is obtained which reveals the presence of new species of particular interest, such as those here described. It is to the indefatigable labours of the late Mrs Gray that we owe most of the material from the Girvan area, and our knowledge of the faunas of its Lower Palæozoic beds is largely founded on her collections. Her daughters, who are carrying on her valuable work, recently sent me the few specimens which form the subject of this paper.

Jan Mayen, so far as at present known, is entirely volcanic in origin. The rocks, therefore, are conveniently grouped with the Tertiary and later volcanics of the Faroes, Iceland, and Scoresby Sound in East Greenland. It should be noted, however, that these three localities are linked together by the Faroe-Iceland Ridge, the water everywhere being shallower than 500 fathoms. Jan Mayen, on the other hand, though lying at the same distance from Iceland as the Faroes, is not on the Ridge, and is separated by depths of over 1000 fathoms. Its position is somewhat to the west of the centre of the Norwegian Sea, and at no great distance from depths exceeding 2000 fathoms.

Jan Mayen is so inaccessible and so infrequently visited that very little geological and petrographical work has been done on the island. Some rocks were collected during the Austrian “Pola Expedition” of 1882–3; and these were described by Scharizer as porphyritic olivine basalts, with one example of ægirine-trachyte. Four analyses were given, but their quality is so poor that they are practically useless for scientific discussion. Washington lists only one of these, and that among the analyses of inferior quality. The only modern petrographic work that has been done on Jan Mayen rocks is the description of an olivine-trachyandesite by Dr Holmes accompanied by a first-rate chemical analysis by Dr H. F. Harwood, which forms a valuable addition to the seven new analyses recorded in this paper.

Whatever may be the worker's views on the origin of the Stegocephalia, and on the relation of the various divisions of the Pisces to one another and to the Amphibia, he cannot but agree that a knowledge of the anatomy and of the embryology of the Polypterini is of paramount importance to all those whose research or teaching is concerned with the evolution of the Vertebrata. So he will understand my pleasure when, through the kindness of Dr F. F. Bond, I was able to obtain from Old Calabar a number of specimens of the less-known genus of the Polypterini, Calamoichthys, which were so well preserved as to be excellent for dissection and, as a whole, quite good for histological detail.

In a preceding paper of this series it was pointed out that the smooth branched axes, which are so common in the Middle Old Red Sandstone of Scotland, cannot be assumed to belong to one kind of plant. They were therefore for convenience referred to as Hostimella sp. It was further shown that three distinct types of sporangia were associated with axes of this general type and, on the characters afforded by the reproductive organs, three species were distinguished. These were provisionally retained under the generic name Hostimella, as H. pinnata, H. globosa, and H. racemosa. In the same paper it was mentioned that the linear bodies borne on the peculiar fossil known as Ptilophyton Thomsoni, Dawson, were almost certainly sporangia. This afforded another reproductive structure borne on a vegetative region, which, if found separately, could only be placed in Hostimella sp. Since, as had been pointed out by Kidston, the generic name Ptilophyton is inadmissible for this fossil, it was placed in the purely provisional genus Hostimella as H. Thomsoni. In the present paper the nature of this interesting member of the Scottish Middle Old Red Sandstone Flora will be more fully considered.