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That the breaking off of the beak in this way might happen, other fossils testify; as, for example, the Sheppey cranium figured by Koenig in his “ Icones” as a Larus ; and by Professor Owen in his “British Fossil Mammalia and Birds," as Halcyornis toliapicus (Plate XVII., fig. 5a), from which the beak is entirely absent. The figures of the lower mandibles of the Montmartre birds given in Cuvier's “Ossemens Fossiles,” show what kind of traces they would leave (Figs. 3, 4), and some markings on the Archæopteryx slab are singularly like the imprint in Cuvier's Plate 155, fig. 1 (see Plate XVII., fig. 4).
In the British Museum there are many specimens of much interest besides this transcendentally valuable and instructive Archæopteryx. There may be seen limb-bones of the gigantic Dinornis, the New Zealand Moa, and the enormous foot-tracks in the Connecticut sandstone. There also are specimens of fossil feathers from Bonn and Aix, and the wonderful eggs of the Æpyornis. There too are strange unnamed bones from the Sivalik Hills of India. And these bird-remains may possess a higher interest hereafter for our readers when they know how rare are the fossil remains of the ancient inhabitants of the air.
EXPLANATION OF PLATE XVII. AND WOODCUTS. Figs. 1 and 2. Supposed beak of Archæopteryx, or fish-head (Fig. 1 being the
impression in the Archæopteryx slab of the beak, or fish-head, Fig. 1,
in the counterpart of the slab). Figs. 3 and 4. Lower mandibles of fossil birds from Montmartre. Fig. 5. Cranium, without the beak, of the Sheppey bird (Halcyornis toliapicus). Fig. 6. Wing of bird (Falco peregrinus). 8, scapula ; h, humerus ; u, ulna ;
r, radius ; c, carpals ; m, mc, metacarpals ; P, phalanges. Fig. 7. Wing of Pterodactyle. S, scapula ; h, humerus ; r, radius ; U, ulna ;
*, pinion (= little finger of human hand). Fig. 8. Part of wing of bat. u, r, ulna and radius ; C, carpals ; me, meta
carpals, or wing-fingers ; t, wing-hook (= human thumb). Fig. 9. Head and jaws of• Pterodactyle (P. longirostris). Fig. 10. Part of wing of Chaja Screamer (Chauna chavaria), with two wing
spurs. Fig. 11. Foot of Archæopteryx (natural size). Fig. 12. Foot of a long-tailed Pterodactyle, from Pappenheim (natural size). Fig. 13. A foot-claw of Falcon. Fig. 14. Fossil remains of the Archæopteryx (about one-tenth linear). C,
costæ ; s c, scapula ; h, humerus ; u, ulna ; r, radius ; è, ilium ; f, femur ; t, tibia ; mt, metatarsus ; P, phalanges ; br, brain ;
b, supposed beak, or fish-head ; x, x', carpal- or wing-hooks. Fig. 15. Carpal-hook or wing-claw of Archæopteryx (natural size).
THE NATURAL HISTORY OF A BEECH TWIG.
BY HARLAND COULTAS.
VERY part of a tree, whether it be leaf, shoot, branchlet, ,
or branch, represents exactly the organic condition of the tree at an earlier period of its life, and one of the stages of development through which the entire tree itself has already passed. For it is plain that the tree was, at the commencement of the first year of its life, a single leaf; and at its close, a green herbaceous shoot, exactly like those annual growths which it now makes at the sides and extremities of its branches. In the spring of the second year, the buds formed by the leaves of the first year at the sides and summit of the first year's growth or shoot, developed into new growths or shoots, which were constructed after precisely the same pattern as the first year's shoot. They presented in autumn, when defoliated, precisely the same external appearances, having side and terminal buds, and the same peculiar form of leaf-scar. We are, therefore, necessarily led to regard them as only a repetition of the first year's shoot. For as the leaf is a unit, through the repetition of which the first year's shoot is formed, so, also, is the first year's shoot itself a unit, but of a higher and more complex character, through repetition of which the branches, and ulti- : mately the entire tree itself is constructed. The whole tree is therefore represented in each of its parts, and if we take the terminal branches or twigs of a tree, and study them carefully, we shall obtain correct views not only of the tree during the first years of its life, but of those general and peculiar laws of growth which govern the entire tree itself.
To render the principle of these researches clearly understood, we have selected a beech twig, which the accompanying plate most faithfully represents.
By looking at Plate XVIII. the reader will see that the primary or central axis of the twig has put forth fifteen secondary axes or side-shoots. The figures in the plate, placed opposite the annular scars left by the winter leaves, will assist the reader in estimating the amount of growth made by the twig year after year; for he has only to bear in mind that these annular scars mark the place of the bud, or the terminal growth of the twig, during the year indicated by the figures, to place, as it were,
VOL. II.-NO. VII.
its exact vegetative condition in a moment before his eyes, at any one of the previous years of its past life.
The twig represented by our plate was cut from one of the lower branches of an old beech, in Epping Forest, on the 7th of March, 1863. As there are thirteen sets of annuli on its main or central stem, it has evidently stopped growing thirteen times, and borne thirteen generations of winter leaves, and as many generations of summer leaves; consequently it is thirteen years old, and it must have commenced growing from the bud in the spring of 1850. It is also plain, that the first and second side-shoots remained in the bud condition throughout the whole of the year 1850, and made their first growth from the bud in the spring of 1851. Hence, only twelve sets of annuli can be counted on these two shoots; and the same law is apparent throughout the entire series of shoots, which are fifteen in number; each is one year younger, and will be found to have one set of annuli less than its parent stem. Thus the fifth branch above, the set of annuli marked 53, is numbered 9, because there are on its surface the marks left by nine generations of winter leaves, or nine sets of annuli; it is therefore nine years old, or one year younger than its parent axis, which numbers ten sets of annuli, counting from annuli marked 53 upwards, to 1862. Similar observations apply to shoots numbered 8, 6, and 4.
We must, however, except shoot 11 numbered 3, and shoot 10 numbered 2. These shoots were formed from buds which were matured in the autumn of 1857 and 1856, or five and six years ago. This is proved by the leaf-scar at the base of the shoot. Yet there are only three sets of annuli on one, and two sets of annuli on the other; consequently the former shoot must have been torpid for two, the latter for four years.
Another feature which presents itself for consideration, is the variation in the amount of stem between the sets of annuli. This shows that the growth varies from year to year, and that powerful growths are sometimes followed by growths greatly retarded. All twigs over whose surface the progress of yearly growths may be traced for a series of years, show more or less these marked differences of growth. Each branch has, in fact, its own peculiar history of growth, and trees differ not more widely in this respect than two branches on the same tree. In the consideration of a tree, we have to deal not with a product of crystallization such as the lead tree, or the dendritic formations on a frozen window, but with matter living and organized. The tree is therefore no stiff, unyielding form, but an easily impressible body, whose growth fluctuates with the favourable and unfavourable state of the weather from year to year.
The distance between two sets of annuli, estimated from the