line in the transverse section of the hair, whilst the Semitic have a more or less angular outline. Formation of Coral Reefs.-Dr. Carl Semper, who has resided some years in the Philippines and is a most accomplished naturalist, has brought forward some objections to Darwin's theory that atolls and barrier reefs imply the gradual sinking of a continent or island, whilst coast reefs necessitate an elevation of its shores. Darwin himself, with his true honesty, mentioned some difficulties to the theory, and Dr. Semper now quotes some observations of islands near the Philippines which certainly do not accord with Darwin's theory. He describes a horizontal surface of colossal dimensions, which could not possibly be formed during a depression which a few miles farther north had produced a channel of 70 fathoms in depth. He rather regards the physical influences, especially the internal seacurrents caused by the rain, and the exterior direct and diverted ones, as the cause which have produced in the north of this district atolls, and in the south the coast reefs, simultaneously with an elevation. Whilst in the south the deep-going eroding action of the wave-blow or the wash of the sea, has gradually planed away the dense and solid coralline limestone to a nearly horizontal surface, which lies at about the depth to which the sea-wash is capable of acting; in the north, the becks coming down from the mountains conjointly with the wash and currents of the sea, have acted much more strongly upon the soft readily decomposable basalt of the west, than was the case with the limestone of the south, and thus has arisen the apparently incompatible conditions of their respective coral growths. A natural Hybrid-Barnacle.-Dr. Fritz Müller, of Desterro, in South America, one of the most able of Mr. Darwin's champions, recently directed his attention to the Barnacles occurring on that coast. He found a species of Sea-acorn (Balanus) which either attaches itself to, or becomes overgrown by various forms of sponge, and it was observed that the third pair of legs or cirri were equipped with numerous teeth, whence he terms it B. armatus. He describes a very remarkable grouping of different species of Balani on a rock, according to depth. The sensitiveness of these animals to luminous impressions is not, he says, dependent on the eyes discovered by Leidy. He took a large Balanus tintinnabulum living, out of its shell and separated it from the operculum, with which the eyes remained in connection. It lay in a saucer of water, with its cirri half unrolled. As often as the shadow of the hand fell upon it, it rolled up the cirri with a sudden movement. In B. tintinnabulum the eyes are very distinct; in B. armatus they have not yet been found. The most interesting observation of Dr. Müller's is, however, the existence of a natural hybrid between B. armatus and B. assimilis which he most minutely describes, and for the existence of which he satisfactorily accounts by the isolation of the respective parents. If, he says, we regard the species of a genus as descendants of a common primitive form, and at the same time, in accordance with the well-known experience of gardeners, regard their various peculiarities as so much better fixed, or so much less variable, the earlier they were acquired, the longer they have been inherited unchanged, it becomes intelligible that, above all, the characters proper to the primitive form persist; and consequently in the crossing of two species, these are more readily transferred to the hybrid than later-acquired peculiarities of the father or mother. From this point of view, Dr. Müller thinks we shall be able to explain many peculiarities of hybrids and, vice versa, perhaps in many cases to trace from the form of the hybrids to the primitive form of the genus; the latter of course only with the greatest care, for the mere fact that the hybrids produced by males of one species with females of another, do not agree with those produced by males of the second species with females of the first, furnishes a proof that other circumstances aid in determining the form of the hybrids. The Ancestry of Insects.-Dr. Anton Dohrn, of Jena, has lately described a new fossil insect, which he calls Eugereon Boeckingi, and which leads him to make some observations on the development of Insects by Natural selection. This Eugereon has characters intermediate between those of the Hemiptera and Neuroptera, and must, says Dr. Dohrn, be regarded as genetically related to the two orders. He does not think, however, that it was the common ancestor of these two groups, for the Neuroptera are found along side of it, but he believes that at a period not much earlier an insect form existed completely intermediate between the Neuroptera and Hemiptera, from which these two orders were differentiated and from which Eugereon also was descended, not having become so much modified. Dr. Dohrn then tells us of Haeckel's views (also a Jena professor) whose book we spoke of as most significant when it first appeared. Haeckel says that Insects, Spiders, Centipedes, and Crustacea must have had a common ancestor. The ancestral form of the Crustacea is known, appearing in their development as the Zoëæ. The ancient adult Zoëæ or Zoepoda, as Haeckel calls them, flourished early in the Silurian period according to that author, and it was probably about the Devonian epoch that certain Zoepods were naturally selected for a terrestrial life, developed trachea and became Protracheata, or progenitors of all the great Tracheiferous group of the articulate-limbed animals; whilst those which remained in the water are the ancestors of the Branchiferous forms called crabs, lobsters, and shrimps. Whether any Protracheatæ still exist is, says Haeckel, doubtful: perhaps the Solifuge, a strange group of aberrant spiders, and also those insects which have no wings (not through disuse as in many cases, but by their progenitors never VOL. V. 2 s developing them) represent amongst to-day's fauna, the Protracheata of the past. Surely it is a pity that the Ray Society did not adopt the suggestion of Professor Newton, at Norwich, to translate so interesting and suggestive a work as that of Haeckel. Rash his speculations may be, but they are of high interest, of much use, and are, at least, noble efforts to grasp truth. The Glass-Rope Sponge. The turmoil caused by this beautiful organism among systematic zoologists has taken a new direction. Professor Lovén has described a sponge which he calls Hyalonema boreale-placing it thus in the same genus as the Glass-rope; and from the examination of this Boreal species he concludes that everyone else has studied the Japanese sponge upside down. The long glassy fibres are, he says, merely the remains of a long pedicle which was attached to a rock, and on which the mass of the sponge was supported. Dr. Gray protests against this inference. Lovén's species is not a Hyalonema at all, but merely a new and interesting pedicellate form, to which there are many similar species. The Rev. A. M. Norman has pointed out several of these, and has shown how their spiculæ differ inter se, and from those of Lovén's Hyalonema boreale, which is also very different in this respect from the true Japanese Hyalonema, or from the reputed Lusitanian species obtained off Portugal. A Viviparous Echinoderm.-Dr. Ed. Grube describes an Echinoid from the Chinese Seas under the name of Anochanus, which actually produces young Echini, like itself, having spines, feet, and even pedicellariæ. These young, though having a general resemblance to the parent, are not quite the same in detail, and must undergo modification with growth. This discovery is of remarkable interest, for it adds one more to the many diverse methods of reproduction known among Echinoderms, and completes the parallel which they present to the Worms. We now know, in both groups, of animals laying eggs which produce embryos developing directly into the adult form; of others which present strange larval conditions which either become completely altered, so as to form the adults, or bud off from their interiors a small mass of living tissue which becomes the adult, leaving the larva to perish. We know, in both groups, of hermaphrodites and of diæcious species, and now we have added a viviparous form of Echinoderm, such as was previously observed in some Nemertian worms. We have yet to discover among the Echinoderms the various modifications of asexual reproduction, by pseudova, fission, or true parthenogenesis; the first two of which methods (especially fission) are so well known among worms. Parasites of the Sea-cucumbers.-A large division of the Holothuridæ abound in parasites, and oddly enough all these parasites belong to groups in which parasitism is quite a rare exception. In the first place there are fishes which belong to the genus Fierasfer, these pass in through the water-tree, or lung, of the animal, they are true parasites, feeding within the Holothuria; then there are several small Crustacea; and thirdly, the Mollusc Entoconcha, described by Johann Müller, from Synapta. Dr. Carl Semper describes these in his work on the Echinoderms of the Philippine Islands, and also mentions a new Entoconcha which lives in a true seacucumber; he also describes parasitic species of Eulima; and most interesting of all, a little Lamellibranch which lives on the skin of Synapta, and crawls with a large membranous foot, whilst its shell is so much invested by the mantle as to be completely internal. An addition to the parasites of the Holothuroid Echinoderms was made last year by Mr. Ray Lankester, who discovered a very remarkable Rotifer in great abundance amongst the genitalia of the Synapta Sarniensis and inhærens, at Guernsey. PHYSIOLOGY. New Bodies discovered by the Spectroscope.-We would direct special attention to the very remarkable report of Dr. Thudichum, issued by the Medical Officer of the Privy Council in his last (tenth) Blue Book. Dr. Thudichum sketches in a masterly manner the history of past chemical researches into the functions and products of the human organism. He then describes some of his own researches, apparently carried out within the year, and which have yielded most extraordinary results. New bodies determined by their optical properties are described in this report at the rate of about three a page. This is rather rapid work, and does not leave a very satisfactory impression on the mind. Some most interesting fluorescent products from the chemical decomposition of blood, of albumen, and of urine are described, of which we are most anxious to hear or see more. The spectroscope used by Dr. Thudichum appears to have been an excellent one; but his method of examining only one thickness of a coloured body, has, we fear, led to some misapprehensions as to new bodies. Some of the spectra drawn as new are highly interesting and no doubt indicate new bodies, as, e. g., cruentine and its products; but others are old and well known to all physiologists, though Dr. Thudichum "reports" them as though previously undiscovered. This is a bad sign, and coupled with the hasty appearance of the work does much to diminish the value of what seems otherwise likely to prove a very notable and grand addition to the knowledge of animal chemistry. Quarterly List of Publications received for Review. 1. The Medical Profession and its Educational and Licensing Bodies. By E. D. Mapother, M.D., Professor of Anatomy and Physiology, Royal College of Surgeons of Ireland. 230 pp. Fcap. 8vo. Fannin & Co. 2. Medical Education and Medical Interests. By Isaac Ashe, A.B., M.B. 170 pp. Fcap 8vo. Fannin & Co. 3. On Aniline and its Derivatives: a Treatise on the Manufacture of Aniline and Aniline Colours. By M. L.A.M. Edited by William Crookes, F.R.S. Reimann, P.D., 180 pp. 8vo. Longmans & Co. 4. Reliquiæ Aquitanice. By Edouard Lartêt and Henry Christy. Parts VI. and VII. 5. Guide to the Goldfields of Nova Scotia. By A. Heatherington. 170 pp. Fcap. 8vo. Trübner & Co. PAMPHLETS, PERIODICALS, AND PROCEEDINGS OF SOCIETIES. Die Darwinsche Theorie und das Migrationsgesetz der Organismen, Memoirs and Publications of the Geological Survey of India. Contributions to the History of Development in Animals. I. On Foetal Circulation. By William Macdonald, M.D., F.R.S.E., Professor of Civil and Natural History, Zoology, and Comparative Anatomy, St. Andrew's. Report of the First Exhibition of the Aëronautical Society of Great Britain. Dr. Walter's Doctrines of Life. 28 pp. 8vo. On the Temperature of the Sea and its Influence on the Climate and Agriculture of the British Isles. By Nicholas Whitley, F.M.S. Some of the Educational Aspects of State Medicine. By H. W. Rumsey, M.D., &c. |