candicans (Weihe), R. sanctus (Schreber), R.
idæus (Lin.), R. caesius (Lin.), R. radula
(Weihe), R. hybridus, R. saxatilis, and R.
chamamorus. Professor Babington, on the
other hand, in his recent works on The British
Rubi, has described forty-five species, of
which forty-one are fruticosi, and would there-
fore be included in Mr. Bentham's R. fruti-
cosus and R. caesius. Herr Gremli thinks
there are 150 species of Rubi in Switzerland,
while Herr P. J. Müller is said to have describ-
ed no less than 500 species, and thinks that
in France alone there are 2000 species.
Even those who admit a large number of dis-
tinct species are obliged to admit also a consid-

diversity of opinion exists as to the origin of the latter. Some deny that any of them are hybrids, while others admit both physical causes and crossing as producing such causes. Professor Babington, whose work supplies evidence enough, if such were wanting, of the extreme difficulty of determining what is, and what is not, a species in the genus Rubus, thinks that the production of hybrids is as repugnant to brambles as to most other plants:

purpose of bringing it up to the then state of the subject. The preparation of it was however interrupted by the author's death in 1866. In the following year the Governor and Council, having been authorised by the Legislature, appointed Mr. W. G. Binney, well known by his Land and Fresh-water Shells of North America, published by the Smithsonian Institution, to complete the book. Dr. Gould did not propose to make much change in the classification; and the editor has respected his views. The first edition was illustrated by fifteen coloured plates, which were to have been reprinted and added to. With this view Dr. Gould had prepared some drawings of nudibranchiata; these and many others supplied by Professor Agas-erable number of varieties; but the greatest siz, as well as several of Tunicata and Cephalopoda, have been printed on 12 coloured plates, which are numbered from 16 to 27 in succession to the 15 plates of the first edition. The latter could not, however, be found; and in the meantime, Dr. Gould's collection of shells had been sold and removed from Boston, so that the editor had to replace the intended reprinted illustrations by new ones, which he has had engraved on wood, from drawings chiefly by Mr. E. S. Morse. These illustrations, which are generally from better specimens than were available to Dr. Gould, are admirably executed. There are often however discrepancies between the new figures and the old desscriptions, chiefly as regards measurements. Owing to the expense of the illustrations, the new edition only embraces the Mollusca; the Bryozoa, Radiata, etc., being omitted. The editor has added some notes and a very valuable bibliography of each species, which greatly increases the usefulness of the book. The careful study of the recent Mollusca of the eastern coasts of North America is of very great importance just now in connection with the fauna of the tertiary epoch, and consequently with biological theory; and it may be hoped therefore that the other local faunas of America will be brought up to the present state of science.

57. THE great variety of forms of the Rubi or brambles, and especially the great number of them which form intermediate links between some of the more or less well characterized species, make the study of the genus Rubus very difficult. How many of this multitude of forms are to be regarded as definite permanent species, and how many as mere varieties? Again, how have the varieties arisen? Are they due to the effects of soil, climate, and other physical agents permanently or casually acting upon parent plants of the same species, or are they hybrids or crosses between parents of different species? The answers to the first question go from one extreme to the other. Thus Spenner considered that there was but one species of fruticose bramble in Europe. Mr. Bentham reduced all the British fruticose brambles to three: Rubus idæus, R. fruticosus, and R. caesius. Among German botanists Herr Otto Kuntze reduced all recorded German brambles to nine species: Rubus fruticosus (Lin.), R.

Those who think that Rubi have an inclination to produce fertile seeds so strong that it results in frequent hybridity make no attempt at proof." He goes on to say that "the assumption of hybridity in difficult cases seems merely a mode of escape from, not the removal of, a difficulty. It is often nothing more than the concealment of ignorance under a bold exterior." This is often true; but the same language may, with even more justice, be applied to the "manufacture" of species. Dr. Kuntze, in addition to the nine species of German Rubi, admitted the existence of twenty-three well-marked varieties, the sult of hybridization. Professor Babington says of these hybrids: "In many cases the supposition seems to me to be very rash, for in this country the supposed parents have not been observed growing in company."

re

Since the publication of Mr. Darwin's views the question of hybrids has entered on a new phase, and naturalists are endeavouring to work out the subject in a much more thorough way than formerly. Since the publication of Dr. Kuntze's work in 1867, Herr Focke of Bremen has made many interesting observations which, if they do not absolutely establish the existence of numerous natural fertile and barren hybrid brambles, prove that something more than an assertion of individual belief in the distinctness of species, or a flippant charge of ignorance or worse against those who hold an opposite view, will be necessary to get rid of the arguments recently put forward. Herr Gremli, who is known for his Excursions Flora der Schweitz, and who shows himself so thorough a believer in distinctness of species as to admit 150 species of Rubi in Switzerland, has been working out the ideas of Herr Focke in a study of the Swiss brambles. Selecting only localities which he could repeatedly visit, and where he could see the plants at several stages of growth, especially when in flower and in fruit, he detected about 150 forms of bram

bles. Rejecting the less characteristic of these, he has published descriptions of thirty-two species, some of which are new, and twelve of which at least are among those described by Professor Babington, and twenty-one hybrids of which he thinks the parentage certain, besides five or six whose parentage was uncertain or unknown. Of the hybrids several had been already noticed, notably by Herr Focke; but several appear to be now for the first time described.

The Rubi which appear to have the greatest tendency to produce hybrids are the Tomentosi, represented by Rubus tomentosus (Borchausen), and the Corylifolii, represented by R. caesius (Lin.) The Glandulosi, on the other hand, either produce no hybrids, or the numerous forms of that group are fertile, and pass into permanent races, or fall back into one or other of their parents. As a general rule, the greater the development of hairs on the underside of the leaf the fewer occur on the upper surface, and the converse. Where, for instance, the lower side is covered with a white or whitish felt or tomentum the upper is naked. R. tomentosus forms however an exception to the rule. The leaves of that plant, as was pointed out by Dr. Kuntze, have on their upper surface, between the venation, very small compressed stellated hairs, which can only be distinguished under a magnifying power of sixty or seventy times. These microscopic hairs afford a means of detecting hybrids between R. tomentosus and other species. R. suberectus (Anders.), a form looked upon by Professor Babington and most botanists as a distinct species, is considered by Herr Gremli as a hybrid of R. fruticosus and R. idæus. The arguments which he adduces are certainly very cogent; but the verification by direct experiment is still wanting. Herr Gremli admits that the fertility of hybrids is weaker than that of their parents, but that nevertheless many of them can be propagated by seed, as Herr Focke has already done in the case of several of the supposed natural hybrids. The objection urged against admitting that varieties are largely due to hybrids, namely, that there ought to be thousands of them annually produced if fertile hybrids are naturally produced at all, is not of much value, because the number of conditions which must concur to produce from two plants of different species a seed capable of germinating is so great, and the circumstances so complicated, that it very rarely happens. Still rarer must be the production of a fertile variety. This subject is of great interest in connection with physiological theory. Herr Gremli's present work is a modest but substantial contribution to it.

the great libraries of Universities. The extent of this new paleontological literature may be judged from a mention of some of the princi pal works on tertiary floras which have appeared since 1856:-Unger's Sylloge Plantarum Fossilium, containing descriptions of 327 species of the tertiary fossil plants of Austria; Professor Oswald Heer's very important work on the tertiary flora of Switzerland; Herr Rudolph Ludwig's investigation of the plants that formed the lignites of the Wetterau; M. Gaston de Sapota's splendid work on the tertiary floras of the south-east of France, and his previous work on the tertiary flora of Provence. It is not too much to say that these works have created tertiary vegetable palæontology. And that the investigation of the floras of the other geological epochs has not been neglected is shown by several recent memoirs of the veteran Göppert, especially his floras of the Transition and Permian periods, Dr. Oldham and Professor Morris's fossil flora of the Rajmahal Hills, Professor Schimper's memoirs on the plants of the variegated sand-stone and transi tion rocks of the Vosges, the important investigation of Professor Constantin von Ettingshau sen on the form and venation of leaves of living and fossil plants, especially his great work on the comparative form and venation of the leaves of living and fossil ferns, and M. L. Lesquereux's numerous contributions to the knowledge of the coal plants of the great American coal-fields.

It is evident from this enumeration that Unger's work, however complete and satisfactory it may have been sixteen years ago, no longer supplies the wants of science; and that a book which should co-ordinate all this mass of new material with the old, and give a syste matic epitome of the present facts of fossil botany, was wanting. Professor Schimper of Strasburg, well known by his own researches on living and fossil plants, has undertaken such a work in two volumes, illustrated by 100 folio plates. The first volume and 50 plates appeared in 1869; the first part of the second volume, and 25 additional plates, were issued immediately before the commencement of the present war. When the rest can appear it is now impossible to say. The descriptive part of the work is preceded by a succinct, useful introduction, embracing a sketch of the history of fossil botany, the state of preservation of fossil vegetables, their distribution according to formations, the differ ent modes by which they have been preserved, the principles to be followed in their determination, the changes which have taken place in the vegetable kingdom from its first origin to the present epoch, under the two heads of disappearance of species and renew58. PROFESSOR UNGER'S Species et Generaal of floras by the appearance of new types, Plantarum, the second edition of which was published in 1856, afforded geologists a systematic account of all the fossil plants known up to that date. Since then, however, a great number of important works on fossil botany have been published, besides many memoirs and notices scattered through the transactions of learned societies, and scientific journals, which are not always to be met with even in

the characteristics of the floras of different epochs, and the application of vegetable palæontology to the climatology and geology of the globe. Notwithstanding the very questionable, if not absurd, expression of La Flore du Monde primitif" which forms part of the title of Professor Schimper's book, his ideas on biological theory are of the most advanced character. He not only rejects the doctrine of the

immutability of species, and the sort of compromise, which some naturalists have proposed, of two kinds of species-homologous species, or those produced by gradual transformation, and analogous or specially created species-but also the primitive or generative types of Mr. Darwin. He says that, the moment we search for the origin of organic beings at all, it is illogical to halt until we reach the primordial cell, or even the primitive protoplasm itself.

tained, we are convinced of their general truthfulness and utility.

59. EXCEPTING the region of the Alps, there is a complete break in the succession of organic life at the end of the paleozoic epoch in Middle Europe; at the end of the Trias an entirely new flora and fauna begin in the Lias; the same thing takes place at the end of the Jurassic period, and, though in a less striking way, at the close of the Cretaceous period. These gaps interpose almost insurmountable obstacles to the development of biological theory; and therefore the filling of them would confer a great benefit on science. The intercalation of the Rhætic beds between the Trias and Lias has contributed in some measure to fill up. one of them. Considerable progress has also been made within the last few years to fill the wide gaps between the Jurassic and Cretaceous periods, by a series of beds containing a comparatively rich and hitherto almost unknown fauna. Herr Oppel was the first to include these beds under the name "Tithonic Stage ;" and already in a very few years, they can boast of a considerable literature, so active has been the controversy about their position -a controversy in which almost all the foremost Continental geologists, Pictet, Hébert, Lerz, Marcou, Chaper, Boutin, Coquand, Oppel, Zittel, Moesch, Waagen, Benecke, C. Mayer, etc., have been more or less engaged.

In the section on the disappearance of species, speaking of the gradual disappearance of the Pinus Cembra from the Alps, where it formerly was abundant, he says that, as this tree exists nowhere in Europe, the species will be entirely extinct when the last tree shall have perished on the Alps. Unless he is of opinion that the Alpine tree known as the Pinus Cembra is different from that of Siberia known by the same name, and certainly representing the Linnæan species, the Cembra, or Zürbelkiefer, is to be found in European Russia, as well as all through Siberia, up to a height of nearly 6000 feet, for instance on the Sajan, and other mountains of Eastern Siberia. The European Russian region of the Pinus Cembra comprises the basin of the Kama in the northern half of the government of Perm, and parts of the neighbouring governments of Vologda and Vjatka, extending along the Ural chain from lat. 57 N. to 61° 20', the most western limit in Vologda being Solwytschegodsk, about 47° E. Long. It is found about the head waters of Rocks of this Tithonic stage are found in the the Petschora and the Mylwa, a tributary of Carpathian mountains, among the Austrian and the Vitchegda, the principal eastern feeder of Bavarian Alps, in the Italian Alps, in Savoy, the Dwina. In this region it never forms con- the basin of the Isère, the Cevennes, about tinuous woods, or is a chief constituent of Marseilles, and even in Spain. Professor Zittel tracts of forest as in Siberia. Although the divides the stage into two groups: 1. The gradual disappearance of this tree from the limestones of the northern of the two remarkAlps will not extinguish the species, the able parallel chains of escarpments of the Carphenomenon is nevertheless well worthy of pathians, most characteristically developed in attention. It is said to have formerly existed the white limestone of Stramberg, and the calon the Carpathians; but we do not know caire supérieur de la Port de France, in the dewhether it has entirely perished there or not. partment of the Isère, etc.; 2. The white and The Pinus Cembra is an essentially glacial tree, red Crinoïdal limestones and breccias of the and very probably existed throughout middle southern chain of escarpments of the CarEurope, along with the rein-deer, during the pathians, especially at Rogoznick, and at Czorglacial period, but gradually retired in recent styn on the Dunajec, on the frontiers of Huntimes, leaving islands on the Alps and Carpa-gary and Galicia; the Diphya-limestone, a red thians, which are fast perishing. That it should perish where the conditions of temperature and moisture are otherwise favourable seems to indicate an important law in the geological life of a species.

limestone rich in Ammonites and terebratulæ, forming the upper part of the well-known Ammonitico rosso of the Venetian Alps; the greenish-grey hard fossiliferous marble of the Central Apennines, most characteristically deProfessor Schimper has given very full bib-veloped at Monte Catria north of Gubbio; and liographical references throughout the descriptive part of his work, which will render it of great use for reference when the index has been published with the last part. Here and there he might however have been more specific with regard to the formation to which the rocks belonged from which the specimens were obtained. Every reader cannot be supposed to have the geological maps of the several European countries always at hand. Having compared the figures of Professor Schimper with a considerable collection of fossil plants, containing specimens from several of the localities whence the plants figured by him were obN-22

VOL. LIIL

isolated masses of red limestone in the Austrian and Bavarian Alps, etc. The red limestone containing Terebratula diphya of Cabra in Spain, and in the white and grey limestones rich in corals and gasteropoda, with Terebratula janitor and T. Moravica in North Sicily, probably also belong to this horizon. Besides these defined groups there are a number of deposits of doubtful position, but probably belonging, at least in great part, to the same horizon as group 2. Such are the limestones of Innwald, Roczyny, Wimmis in Switzerland, Mont Salève near Geneva, and the couches à Terebratula Moravica in the south of France.

The first group, which Professor Zittel pro- | poses to call the "Stramberg beds," contains a rich fauna, which approaches in character very much to the cretaceous. He published some time ago, under the title of Cephalopoden der Stramberger Schichten, a monograph of the fossils of this group. He has now added a well illustrated monograph of the forms occurring in the rocks of group 2, or rather of those of the three well-established localities-the Carpathians, Venetian Alps, and Central Apennines. He proposes to call these beds the "Rogozniker beds," or the zone of Terebratula diphya. The fauna of these beds consists almost exclusively of the Shelled Mollusks and delicately organized Crinoïds, a small number of Echinoids and isolated corals. Besides a crocodile skull, now in the museum of Padua from Tre- | schè in the Setta Communi, which Cuvier compared to the gavial of Honfleur, and the teeth of fish of the genera Lepidotus, Strophodus, and Sphenodus, there are mentioned or fully described in his monograph 7 Dibranchiata, 79 Tetrabranchiata, 3 Gasteropoda, 12 Elatobranchiata, 23 Brachiopoda, 6 Echinoidea, 5 Crinoidea, 2 Corals-making a total of 137, or, including the fish, 140 species. Of these species 107 occur in the Carpathians, 17 in the Austrian and Bavarian Alps, 70 in the Venetian Alps, and 59 in the Apennines. The preponderance of species in the Carpathians is due to the Brachiopods and Elatobranchs, which occur only sparingly in the other districts. Excluding the Austrian and Bavarian or Northern Alps, there are only 9 species peculiar to the Venetian or Southern Alpine Diphya-limestone, and 6 to the Apennines. Of the 70 South Alpine species, 44, or 63 per cent., occur also in the Carpathians, and 39, or 55 per cent., in the Central Apennines. Of the 59 species forming the entire fauna of the latter, 40 are common with the Carpathians, or nearly the same as with the Southern Alps.

The Rogozniker beds cannot be paleontologically equated outside of the Alps; stratigraphically, however, their position is well defined. They are bounded above either by beds of the Stramberger group, or by lower cretaceous beds; below they are bounded by the zone of Oppelia tenuilobata, or, as Professor Hébert proposes to call it, the zone of Ammonites polyplocus. This zone has been recently traced, independent of its more eastern extension, at different parts of the Carpathians and Alps, along the whole northern margin of the south European sea, from Streitberg and Passau, through Franconia, Suabia, and the Swiss and French Jura. It follows the ancient northern shore along the southern declivities of the French central plateau, where, at Valence and in the Cevennes, it is typically developed. Further to the west the horizon becomes uncertain; but, as the zone of Ammonites transversarius is developed at Niort, almost as at Birmensdorf, Professor Zittel thinks that the zone of Ammonites polyplocus may be sought for with considerable probability of success in the Coralline and Kimmeridge beds of La Rochelle.

Adopting the view of most geologists that

d'Orbigny's Etage Corallien must be regarded as only a coralline facies recurring in several different horizons, and keeping in view the intimate connection of the Rogozniker beds with the zone of Ammonites tenuilobatus, and their sharp stratigraphical and paleontological separation from the lower chalk, these beds may be considered to be (1.) in any case, younger than the upper Oxford group, and corresponding consequently to the whole or a part of the overlying Jurassic rocks, and (2.) younger than the Kimmeridge series (if the zone of Amm. tenuilobatus be equated with the newer or the whole Kimmeridge group), and corre sponding therefore either to the highest strata of this stage or the Jurassic deposits between it and the lower cretaceous rocks. If the Tithonic stage be considered as a whole, Professor Zittel thinks that the relations of the older portions with Jurassic rocks are more numerous and definite than those of the Stramberger or upper beds with the lower chalk; and he consequently makes the stage the last division of the Jurassic.

60. THE places where the opposite electricities appear on the faces of crystals when they are heated or cooled are generally spoken of as poles which may be supposed to be connected by lines considered as electrical axes. In those cases where the electricity is developed in a terminal polar form, these opposite poles coincide with the ends of diameters of the crystals. Reiss and G. Rose concluded from their experiments that when topas and prehnite were heated, only poles of the same name were to be found on their surface, and that consequently the opposite poles should be assumed to be in the centre of the crystal. Hence they called such crystals centro-polar. Herr Hankel on the contrary held that there was a peripheric distribution of the poles in those minerals also. The full details of his experiments on the pyroelectricity of Topas are now published as the eighth of his memoirs on electricity, two others of which also treated of the pyro-electricity of crystals (boracite and quartz). While these experiments fully confirm the view of the peripheric distribution of opposite electricities, they show that that distribution is by no means so simple or symmetrical as the usual assumption of electrical axes implies. The experiments on topaz have increased and extended the knowledge of the general subject in other respects also.

The following are the general conclusions to which Herr Hankel has arrived:-1. The thermo-electricity of crystals is not caused by hemimorphism, but seems to be a generic property of all crystals, whenever their other physical relations allow of the occurrence of electrical energy, and its accumulation to a measurable extent. 2. As both ends of the same axis in holomorphic, or at least in nonhemimorphic crystals, are crystallographically of the same value, they must exhibit similar electrical behaviour, and therefore exhibit the same polarity where they really attain to an equal development. 3. The distribution of electricity on non-hemimorphic crystals de