brane and the lower, which separates them from the ovary, and the anthers, closely applied, are apparently quite connate and together adnate to the stigma. We have observed in soaked specimens what we have every reason to believe are true pollen granules, with their tubes penetrating the tissue of the stigma.

The contents of the ovary do not appear to differ in the normal and abnormal flowers. In Campanula colorata we have seen flowers intermediate in character between those above described, and normal ones, in which the corolla, instead of being imperforate, opened by teeth in the centre, though falling short of the calyx-lobes in length, -the style considerably lengthened and the anthers free. In connection with the occurrence of dimorphous flowers in Campanulaceæ, it may be well to bear in mind that the method of fertilization of the normal flowers was long a puzzle to botanists. For a detailed notice of the various hypotheses suggested to explain it we must refer to M. A. de Candolle's Monographie des Campanulées (1830) and especially to M.M. Brongniart* and Tulasne'st Papers in "Annales des Sciences Naturelles." In these flowers the anthers open and discharge their pollen before the expansion of the corolla. M. Du Petit-Thouars conjectured that the stigmas were fertilized before it opened. He found that the stigmatic lobes were slightly divergent in the bud at a time when the anthers might be supposed to open and that they again close shortly before the corolla expands : after its expansion they are once more divergent. This view was considered to be supported by the case of the allied Goodenies and Scaevolae in which the pollen is received into a capsule or indusium terminating the style before the flower opens. When the corolla expands the indusium in these plants is closed. Again, much attention has been directed to what have been termed the 'collecting-hairs' with which the style in the Bell-flowers is so frequently clothed. A function has been attributed to them in the fertilisation of the flower, but this, as Brongniart showed was due to imperfect observation. These hairs, which brush off the remaining pollen from the anthers as the style shoots up through them, frequently become invaginated, like the finger of a glove drawn back half way up: the sheathing portion entangles a few of the grains so that they appear actually drawn into the tissue of the style: hence the mistake. M. Tulasne, whose observations are of the highest authenticity, finds that pollen received upon the stigma produces the tubes which fertilize the ovules. How the pollen reaches the stigma must be more fully settled by careful observation. It is highly probable that insects play an important part in its conveyance, as various observers have suggested. There are other plants belonging to different Natural Orders to those above noticed, which offer like dimorphism. In Caryophyllaceae, Maximowicz,‡ describes a Stellaria (dis† 3e Sér. xii. 71.

* 2e Sér. xii. 244.

Primitiae Fl. Amurensis, 57.

tinguished generically under the name of Kraschenikowia), "floribus superioribus sterilibus, infimis (radicalibus) anantheris fertilibus carnosulis." The flowers from the axils of the lower leaves become buried in the soil and are described as " floribus * * clausis

petalis staminibus stylisque nullis, capsulae rotundatae parietibus carnosis, seminibus fuscis * * embryone peripherico arcuato albumineque normali! donatis." The normal flowers are petaloid with the stamens nearly equalling the sepals. He says, "verosimillime capsulae intra paniculam steriles." M. Weddell* and Asa Gray,t describe dimorphism in the genus Impatiens: M. Weddell in the common I. Noli-me-tangere. In this plant some of the fruits ripen without the previous expansion of the flowers to which they belong. All the whorls of the flower exist, but excepting the ovary, they are extremely small and rudimentary, uniting into a little hood, which the fruit, in elongating, bears up with it and wears as a cap. These abnormal flowers arise near the normal ones, but usually in lateral peduncles. Dr. Gray gives some interesting particulars respecting the structure of the normal flowers of the American species, in which certain membranaceous appendages of the filaments are connivent and more or less coherent over the summit of the pistil, entirely preventing the access of pollen in the greater proportion of even fully developed flowers, which, consequently, fall away unfertilized. In some, however, the growing ovary pushes the stigma through the cap, thus securing its fertilization.

M. Jussieu records dimorphous flowers in the section Meiostemones of the Natural order Malpighiaceae. In Acanthaceae (Ruellia) it was long ago observed by Dillenius. And we might adduce other instances, but these must suffice, for we possess no instance of this kind of dimorphism, referred to our second category, which has been fully and satisfactorily described, much less explained; indeed the examples which we have given are amongst the most marked and the best observed.

The main feature and that to which we would wish to direct attention in, at least some, of these cases, is the occurrence of a second kind of flower in which it would seem that nature has especially contrived to exclude the possibility of fertilization by other than own-flower stamens. It is true that the anthers in the closed flowers of Viola and Oxalis are stated never to have been found open, but in the Campanula observed by us the pollen evidently had access to the stigma; and indeed, M. Michalet points out, as we have said, the existence of fine threads connecting the anthers with the stigmas in the "hermetically closed" flowers of Oxalis. These fine threads, there can be no doubt, are the pollen-tubes. It is impossible that we should here enter upon the role of these remarkable flowers in the economy of the species to which they belong. We do not possess, as we have already said, a sufficient basis of

*Jussieu, Malpighiacées, 85.

Gen. United States, ii. 131.

facts to work upon. It must suffice to suggest conjecturally that a conservative agency, if we may so term it, is at work in the vegetable kingdom, over and above the inherent check of a like tendency possessed in a high degree by the great majority of species, which absolutely prevents miscellaneous or wide hybridization or crossing. We do not forget that the question of hybridization of distinct species may be entered upon, to a certain extent, apart from that of the crossing of different individuals of the same species, and that a most important distinction may be drawn between them, but facts fail to show how far the check which prevents a crossing of species operates in preventing too wide a crossing of individuals of any one species, if indeed it operate in the latter case at all. We have alluded to what have seemed to be special contrivances in certain flowers to prevent self-fertilization. Several familiar cases might be quoted but we have already exceeded a reasonable limit, and until some more careful observers, with a measure of that earnest diligence in an unprejudiced search after truth, which so pre-eminently characterizes Mr. Darwin, shall have described to us the true character and end of some of these anomalous structures it would be useless to offer any blind speculations with regard to them. Finally, let us beg those who have opportunity,-and but a short time each day, if perseveringly devoted to the purpose, will suffice for important results,-let us beg that they will select for careful watching and study either one of the common cases of dimorphism mentioned above, or some of the plants which we have adverted to as offering obstacles to self-fertilization. Either class promises well to be resultful. Let us just observe that it is by no means essential that the observer should be a "botanist." Mr. Darwin is not a botanist, nor did he ever pretend to be such, yet his observations prove of the very highest value to botanical science.

[In the above paper we have not referred to the phenomenon of dimorphism exhibited by various Orchidaceae. We hope to return to the subject, in connection with Mr. Darwin's new work on the "Fertilisation of Orchidaceae' in a future number.]

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Original Articles.

By

XXVI. ON THE EVIDENCE OF THE ANTIQUITY OF MAN, AFFORDED
BY THE PHYSICAL STRUCTURE OF THE SOMME VALLEY.
John Lubbock, Esq., F.R.S.

WHILE We have been straining our eyes to the East, and eagerly watching excavations in Egypt and Assyria, suddenly a new light has arisen in the midst of us; and the oldest relics of man yet discovered, have occurred, not among the ruins of Nineveh or Heliopolis, not in the sandy plains of the Nile or the Euphrates, but in the pleasant valleys of England and France, along the banks of the Seine and the Somme, the Thames and the Waveney.

So unexpected were these discoveries, so irreconcileable with even the greatest antiquity then assigned to the human race, that they were long regarded with neglect and suspicion. M. Boucher de Perthes to whom we are primarily indebted for this great step in the history of mankind, published his first work on the subject, "De l'industrie primitive, ou les arts et leur origine," in the year 1846. In this he announced that he had found human implements in beds unmistakeably belonging to the age of the drift. În his "Antiquités Celtiques et Antédiluviennes" (1847), he also gave numerous illustrations of these stone weapons, but unfortunately the figures were so small and rude, as scarcely to do justice to the originals. For seven years M. Boucher de Perthes made few converts; he was looked upon as an enthusiast, almost as a madman. At length, in 1853, Dr. Rigollot, till then sceptical, examined for himself the drift at the now celebrated St. Acheul, found several weapons, and believed. Still the new creed met with but little favour; prophets are proverbially without honour in their own country, and M. Boucher de Perthes was no exception to the rule. At last, however, the tide turned in his favour. Dr. Falconer, passing through Abbeville, visited his collection, and made known the result of his visit to Mr. Joseph Prestwich, who, accompanied by Mr. John Evans, immediately proceeded to Abbeville and examined carefully not only the flint weapons, but also the beds in which they were found. For such an investigation our two countrymen were especially qualified: Mr. Prestwich from his long examination and great knowledge of the more recent strata; and Mr. Evans as having devoted much study to the stone implements belonging to what we must now consider as the second, or at least the more recent, stone-period. On their return to England Mr. Prestwich communicated the results of his visit to the Royal Society,* (On the Occurrence of Flint Implements associated

* Phil. Transact. 1860.

with the remains of extinct species, in beds of a late Geological Period, May 19, 1859), while Mr. Evans described the implements themselves in the Transactions of the Society of Antiquaries (1860).

Shortly afterwards Mr. Prestwich returned to Amiens and Abbeville, accompanied by Messrs. Godwin Austen, J. W. Flower, and R. W. Mylne. In the same year Sir Charles Lyell, whose opinion on the subject was naturally expected with great interest, visited the now celebrated localities. In 1860, I made my first visit with Mr. Busk and Captain Galton, under the guidance of Mr. Prestwich, while Sir Roderick Murchison, Professors Henslow, Ramsay, Rogers, Messrs. H. Christy, Rupert Jones, James Wyatt, and other geologists, followed on the same errand. M. L'Abbé Cochet, therefore, in his 'Rapport adressé a Monsieur le Sénateur Préfet de la Seine-Inférieure," (1860) does no more than justice to our countrymen, when after a well-merited tribute of praise to M. Boucher de Perthes, and Dr. Rigollot, he adds, "Mais ce sont les Géologues Anglais, en tête desquels il faut placer d'abord M.M. Prestwich et Evans, puis M. "M. Flower, Mylne, et Godwin Austen, et enfin Sir C. Lyell. qui ont fini par élever à la dignité de fait scientifique la "découverte de M. Boucher de Perthes."

66

Soon after his return, Mr. Prestwich addressed a communication to the Academy of Sciences through M. Elie de Beaumont, in which he urged the importance of these discoveries, and expressed a hope that they would stimulate "les géologues de tous les pays à une "étude encore plus approfondie des terrains quaternaires." The subject being thus brought prominently before the geologists of Paris, M. Gaudry, well known for his interesting researches in Greece, was sent to examine the weapons themselves, and the localities in which they were found.

M. Gaudry was so fortunate as to find several flint weapons in situ, and his report, which entirely confirmed the statements made by M. Boucher de Perthes, led others to visit the valley of the Somme, among whom I may mention M.M. de Quatrefages, Lartet, Collomb, Hebert, de Verneuil, and G. Pouchet.

In the "Antiquités Celtiques," M. Boucher de Perthes suggested some gravel pits near Grenelle at Paris, as being, from their position and appearance, likely places to contain flint implements. M. Gosse of Geneva has actually found flint implements in these pits, being, I believe, the first discovery of this nature in the valley of the Seine.* In that of the Oise a small hatchet has been found by M. Peigné Delacourt at Précy, near Creil.

Dr. Noulet has also found flint weapons with remains of extinct animals at Clermont, near Toulouse.

* M. L'Abbé Cochet states (1. c. p. 8) that similar weapons have been found at Sotteville, near Rouen, and are deposited in the Musée d'Antiquités. There seems, however, to be some mistake about these specimens, at least M. Pouchet, who received us at Rouen with the greatest courtesy, was quite unaware of any such discovery.