(vol. ii. p. 147) in the following numbers, expressing approximately the temperature of the Miocene districts :—

The Quaternary Period (newer than the Pliocene, which is not represented in Switzerland) has left the lignites of Dürnten and Utznach, formed after the Miocene strata had been tilted up with the flanks of the Alps. Their flora and fauna approximate closely to the groups now living; but the Elephant and Rhinoceros were inhabitants of Europe. Glacial sands, gravels, and blocks lie over the lignites, and lead us direct to such natural-history and physical conditions as now rule in the highest Alps. The chapter on "Glacial History" well describes these phenomena, and connects them with the hypothetical history of the great interval between the Quaternary Period and our own day.

Chapters XIV. and XV. conclude M. Heer's work with (1) a brief view of the succession of periods and their life-groups; (2) of the possible causes of the upheaval and depression of land during perhaps incalculable time; (3) of the results of these movements, as shown by Switzerland, both in the formation of strata and in the conditions of the surface as eroded by water, ice, and weather; (4) of the possible course of nature in "the remoulding of species," with regard to which, the author remarks, we are still in the dark, and which he does not consider the Darwinian theory competent to explain *.

Thus, with great skill and in a pleasant style, has the Rev. Dr. O. Heer epitomized the geological history of Switzerland, and much of Europe at the same time, keeping before us the great features of

The editor has appended, pp. 295-302, Prof. Rütimeyer's description (with woodcut) of a group of pointed sticks and wattle or basketwork, found in an Interglacial lignite at Wetzikon, and regarded as the handiwork of primæval man. He has also given, p. 303, a comparison of English and Continental measures, weights, and thermometric scales, for the use of the student.

land and sea, faunas and floras, however much they shifted from age to age-as the scenes of a theatre, or the pictures of a magiclantern, change under the skilful guidance of the manager, to illustrate the various turns of a story or a whole series of historic events.

Woodward's Geology of England and Wales' is another good book epitomizing geological history-but in this case by referring mainly to facts relating to inorganic nature, such as the various successive strata in their order, and not as to the extent and conditions of their areas of formation, and referring to fossils only as the distinctive coinage of each period, preserved in the strata, and not as directly suggestive of the animated features of the fauna and floræ once occupying the long-since wasted regions.

After a lucid Introduction, treating of the meaning, objects, and methods of Geology, the author proceeds to describe each formation in detail, as to its topography, lithological characters, thickness, leading fossils, and economic productions. The Malvern gneiss and some other very old rocks of doubtful age serve as the basis of the Laurentian section; and the other formations follow in order, from the Cambrian (treated in the Sedgwickian sense) to the Quaternary gravels and brick-earths. The Igneous and Metamorphic rocks and Mineral Veins are separately noticed (Chapter XII.). Springs, Swallow-holes, Tufa, Caverns, Landslips, Blown Sands, Submarine Forests, Peat, Soils, and " 'Grey Wethers are all briefly considered. Denudation and Scenery, and the Sections exposed by the chief Railways, are also treated of in Chapter XIII., well worthy of study. Chapter XIV., on "Geology in the Field " and other matters, should be read in connexion with the Introduction (p. 1).

Mr. Woodward's work is careful and conscientious; and he shows a healthy desire to refer directly to originators of theories and discoverers of facts; though sometimes a ready reference to the writings of his colleagues in the Memoirs of the Geological Survey has hindered his doing justice to more original notices-for instance, in the case of Swallow-holes in the Chalk, at p. 346, and the "Grey Wethers" at p. 364. Conciseness has been successfully aimed at; and yet the amateur, student, and professor will each for himself find a rich mine of facts and inferences in the short chapters of this compendious and well-conditioned book. A glossary of geological terms, a synopsis of the animal kingdom, having especial reference to fossil forms, bibliographical lists, and an excellent index satisfactorily complete the work.

In conclusion, we heartily recommend these works by Mr. Oswald Heer and Mr. Horace Woodward to geologists wishing to find the position and nature of the strata and the natural history and geography of the times of their formation. There are many points of geological detail, perhaps in every chapter of each book, that are not yet quite settled, or that at least may be further elucidated with advantage; there are omissions too, which the author's line of thought, or the plan of his work, or want of space, did not allow of

being filled up; but the general truth of the deductions is none the less for such slight imperfections. If all is not, and cannot be, yet known about transmutation of species, the great changes of climate, the origin and metamorphism of rocks, and the antiquity of man, yet the main outline of geological history has been fairly sketched to the satisfaction of inquiring minds, and is suggestive of some of the grandest ideas of which the mind of man is capable.

PROCEEDINGS OF LEARNED SOCIETIES.

ROYAL SOCIETY.

April 6, 1876.-Dr. J. Dalton Hooker, C.B., President, in the Chair.

Supplemental Note to a Paper "On the Structure, Physiology, and Development of Antedon (Comatula, Lamk.) rosaceus." By WILLIAM B. CARPENTER, M.D., F.R.S.

Since my communication of the above-cited Paper to the Royal Society on the 16th December, 1875, two important contributions to the Anatomy of Antedon have appeared-one by Dr. Ludwig, chiefly based on his study of Antedon Eschrichtii ("Zur Anatomie der Crinoiden," Zeitschrift für wissenschaftliche Zoologie, Bd. xxvi. 1876, p. 361, continued in Nachrichten von der Königl. Gesellschaft der Wissenschaften und der G. A. Universität zu Göttingen, No. 5, Feb. 23, 1876), and the other by Prof. Greef, of Marburg (Sitzungsberichte der Gesellschaft zur Beförderung der gesammten Naturwissenschaften zu Marburg, January 1876), both of which seem to have been prompted by the appearance of Professor Semper's short paper on the subject. These able observers fully concur with me, as to all essential particulars, in the account I have given of the triple canal-system of the arms, which M. Edmund Perrier not only could not himself find, but ventured to predict that no one else would find; in fact, Professor Greef's figure of a transverse section of an arm might have been copied from one of the drawings I have had by me for more than ten years, save for one slight additional feature. The German investigators also accept the correctness of the statements made by me in my First Memoir, that the "nerve " of Müller is really the genital rhachis, and that Müller's "vessel" in the arms is solid, not tubular-though neither is disposed to believe with me that this "axial cord" is a The character of a nerve, on the other hand, is assigned by Ludwig to a fibrillar band lying beneath the epithelial floor of the ventral furrow of the arms; which band had been independently

nerve.

noticed by my son, Mr. P. H. Carpenter * (who is at present working in the laboratory of Professor Semper at Würzburg), in two of Professor Semper's Philippine species, Actinometra armata and A. nigra, as also in Antedon Eschrichtii, in which it had been previously discovered by Ludwig. It is not nearly so distinct, however, in A. rosaceus; but its existence in that species was also independently recognized by Professor Huxley, who, like Ludwig, was led by his general view of the homologies of the Crinoids to regard it as a nerve. My son regards both the ventral band of Ludwig and my "axial cord" as belonging to the nervous system, being led to that conclusion, as regards the former, by its homology with the radial nerves of other Echinoderms, and, as regards the latter, by the very definite branching he has discovered in the axial cord of the arms of Actinometra armata and A. nigra-two pairs of branches running on each side towards the dorsal surface, and two towards the ventral, where he has distinctly traced their ramifications as far as the leaflets bounding the ventral furrow. Prof. Greef, on the other hand, describes the whole epithelial floor of the ventral furrow as a nerve, on the ground that its histological character resembles that of the nerves of other Echinoderms.

Having recently had an opportunity of examining at Würzburg the very thin sections prepared by my son, I can say with certainty that the fibrillar band is quite distinct from the layer of columnar epithelium which it underlies; but it appeared to me to send off very minute fibrils that pass up between the cells of which that layer is composed.

To myself it appears by no means improbable, looking alike to its position and to its histological characters, that this band is a nerve; but having regard to its immediate proximity to the sensory (ventral) surface, and to its separation from the muscles by the interposition of the triple canal-system, I cannot but think it more likely that it is functionally related rather to the former than to the latter-in other words, that it is an afferent rather than a motor nerve.

As it seemed to me that important evidence might be obtained on this point from experiments made on the living animal, I took the opportunity afforded by my recent visit to the Zoological Station at Naples to institute such experiments; the results of which I am desirous of appending to my paper, as they seem to me to place the doctrine advocated in it beyond reasonable doubt.

Every one who has had the opportunity of observing the habits of the living Antedon well knows the peculiarly rhythmical and symmetrical swimming action which it executes when it spontaneously leaves or is detached from the anchorage afforded by the grasp of its dorsal cirri. Each of its five rays divaricates into two arms, which may be characterized (like the two legs proceeding from the human trunk) as the right and the left respectively; and the act of swimming consists in the alternate

Remarks on the Anatomy of the Arms of the Crinoids," in the Journal of Anatomy and Physiology for April 1876, p. 571.

consentaneous advancement of the five right and then of the five left arms, each of which is bent forwards in a curve which resembles that of the swan's neck in its graceful arch, and is then straightened backwards. The perfect similarity of the movements of all the five arms that work together, involving the conjoint contraction of several hundred pairs of muscles, seems to me to point almost certainly to coordination through a nervous centre; and it will be seen that experiment has fully confirmed that conclusion.

It will be recollected that the centre of what I regard as the motor nervous system is the quinquelocular organ contained in the centro-dorsal basin, which Müller (who did not recognize its cavitary subdivision) characterized as a heart. Müller's view of its nature is still upheld by Greef (loc. cit.), who says that it gives off vessels to the cirri, and regards what I have described as a circular commissure (analogous to the "circle of Willis ") as a closed blood-vascular system in connexion with this, although he admits that the axial cords of the arms, which are derived from this ring, are solid. The careful and repeated investigations I have made on this point, however, have fully satisfied me that my previous statement was correct. There is no passage whatever out of the chambers into the axial cords either of the cirri or the rays; and in the pedunculate Crinoids, as in the early Pentacrinoid stage of Antedon, there is no ventricular dilatation, the solid radial cords directly arising from the axis.

Experiment 1.-Taking up a large and vigorous specimen of Antedon, I turned the entire visceral mass out of the calyx, leaving behind it, therefore, as the centrum of the animal, only the calcareous segments of the calyx with their muscles and ligaments, the centro-dorsal basin with its cirri, and the five-chambered organ contained in the cavity of that basin. On replacing the animal in the water, it executed the usual swimming movement as perfectly as the entire animal had previously done.

Experiment 2.-I removed from a second specimen, which I took out of the water in the act of swimming, the entire centrodorsal basin, with its contents and appendages, leaving every other part as it was. On replacing the animal in the water, all the arms were rigidly straightened out, apparently by the action of the elastic ligaments, which the muscles were powerless to antagonize.

This second experiment, then, not only confirmed my previous belief that the source of the perfect coordination of the swimming movements lies in a Nervous centre, but seemed to establish beyond doubt that the quinquelocular organ is the instrument of that coordination-the centre of a Nervous system, whose peripheral portion consists of the axial cords of the rays, arms, and pinnules. On the other hand, the first experiment, taken in connexion with the second, clearly shows that nothing contained in the visceral mass is essential to the perfect coordination of the swimming movements. And since it is clearly in the oral ring that we should expect to find the centre of any nervous system