more nearly related to the Actíniæ than to the Alcyònia, and that each individual was a perfect animal *, capable of performing those motions which were necessary for its preservation and assistance." I perfectly agree with this gentleman; and when we consider its structure and economy, and, particularly, that this zoophyte does not appear to have possessed tentacula, this simple expansive pouch must be placed among the gelatinous zoophytes, below the Actínia and Hydra. The Ventriculites are met with in this country, in every part of the chalk formation, from the uppermost beds to the grey chalkmarl.

I must defer my observations on the species of this genus to a future leisure.

November 10. 1828.

Yours, &c.

C. B. ROSE.

* Mr. Miller, the author of the elaborate work on the Crinoidea " thinks this opinion is erroneous, and that each ventriculite should be regarded as an aggregation of polypes." I cannot but think, that when this talented and indefatigable naturalist has given to this fossil body the same minute and patient examination he bestowed on the Encrinites, he will coincide with us.

I

342

PART II.

REVIEWS.

ART. I. Picture of Organised Nature, in its spreading over the Earth. By WILBRAND and RITSEN. Pamphlet, in 12mo, pp. 90., and a Map, or Picture, 2 ft. by 4 ft. 3 in., coloured. London. Translated from the German. 15s.

WITH every disposition to profit from this pictorial view of organised nature, we fear we have not been very successful. The object of the production is useful, as leading to comprehensive views; but the plan not sufficiently clear and obvious for general comprehension. The authors, as it appears to us, have failed in their objects, by endeavouring to show the influence of two laws, latitude and elevation, in one picture, instead of making use of two pictures. The distribution of organised beings, according to the laws of latitude, would have been rendered clearer by writing the natural orders on a map of the world on a large scale; and their distribution, according to the law of elevation jointly with latitude, by sections of the principal mountains of the different zones of both hemispheres; or by sections of an imaginary mountain for each zone. Useful general ideas, we think, might be communicated in this way; but the only effectual manner to convey through the eye a correct knowledge of the geographical distribution of plants and animals, is by devoting a map of the world to each particular order. As natural history advances, and the art of writing books on it improves, it may become the practice to accompany the description of each particular order, or even genus, with a map, and sections of the earth's surface, and the proportion and particular parts of them occupied by that order or genus delineated and rendered conspicuous. Thus, supposing the geographical distribution of any order, any Dulgodiàceæ for instance, were to be delineated, the place which that order occupied on the flat or general surface of the earth, i. e. its distribution according to the laws of latitude, would be represented by shading, or marking with colours or dots on the plan ( fig. 102. a b c d); and its distribution in both

hemispheres, according to the law of elevation, by similar markings on the elevations of the typical mountains where it was found (fg). Types might be formed for the printer, representing skeleton maps and sections, such as we have described; and the situation of the order or genus might be filled in

Tropical

with other types representing dots, so that this description of illustration would cost little more than common printing. The distribution of plants and animals, according to the laws of soil and civilisation, is of much less consequence, and much more easily described and remembered, than their geographical distribution.

We shall now endeavour to give some idea of the plan adopted by MM. Wilbrand and Ritsen. A correct idea of their picture may be formed by imagining our figures 103. and 104. joined in one by the line a a. These figures, when joined together, represent an island of mountains rising out of the ocean, with imaginary straight lines radiating from a centre, and imaginary elliptical lines forming parallels above and below the base line of the island.

The Chimborazo mountain (fig. 104. b) is the highest in the centre; the Himalaya mountains of Asia (fig. 103. c), upwards of 25,000 ft. in altitude, are the highest to the left; and the Descabezado (fig. 104. d), in Chile, is the highest to the right. The snow line, or that which in every part of the globe sets the limit to organised beings, as regulated by latitude, begins at 75° N.L. (fig. 103. e), and 60° S. L. (fig. 104. f); as governed by elevation, it begins under the equator at a perpendicular height of say 17,000 ft. (figs. 103. and 104. g); in the 19° N. L. 15,000 ft., in the 35° N. L. 11,000 ft., in the 43° N. L. 8,600 ft., in 62° N. L. 6000 ft., gradually decreasing to 75° N.L., where it is at a level with the sea. The snow line in the southern hemisphere, whether as influenced by latitude or elevation, is little known; but in the picture it is regulated so as to harmonise with the line in the northern hemisphere, and with such facts as have been discovered. The sea at both poles is covered with ice; in the southern hemisphere (fig. 104. h) in a larger, in the northern (fig. 103. i) in a smaller, proportion. The land, if any exists under this ice, is without organised life, except in

some parts where the snow melts, and exposes the surface rocks or soil a part of the year. There minute lichens adhere to the surface, and animals, chiefly insects and birds, are occasionally found; but where the surface is enveloped with eternal snow, vegetation ceases, animals die, and the inquisitive disposition of man terminates.

"But besides this perpetual line of snow, there is another, constantly varying according to the seasons. In the northern hemisphere, after the autumnal equinox, this line gradually becomes lower; being in the winter, according to circumstances, even in the middle of the temperate zone, at the level of the sea; on the contrary, in the southern hemisphere, as the sun reaches the southern tropic, the line rises, till it joins the perpetual snow; and as the sun returns towards the northern tropic, it again gradually descends towards the sea. Thus organic life fluctuates perpetually from north to south, and from south to north. It is this varying line of snow which intimates to birds of passage their time of migration."

In the picture, the detached mountains, as well as continuous ranges, which are, in the five parts of the globe, elevated above the perpetual line of snow, are delineated according to their latitude, and their names and height are marked on them; but of course in such a picture it is impossible to give any idea of their longitude. Thus the Himalaya Mountains of Asia (fig. 103. c), the highest in the world, are placed between

the 30° and 40° N. L. from the meridian, or centre of the picture (a a); and Mount Etna, a small part of which is above the summit of the snow line, is shown in 37° N. L. (fig. 103. k), with a part of the Mediterranean Sea at its base (fig. 103. 1). To preserve a sort of harmony in the appearance of the picture, a line (e a a f) is drawn to represent the boundary of organic

life in the depths of the ocean.

"Whether in the sea there be depths where no creature is able to live, or whether a boundary be assigned to organic life within those depths, cannot be ascertained. It, however, clearly appears from the observations made by Biot, and other naturalists, that fishes, according to their different dispositions, live in different depths of the ocean." Curved lines parallel to this line of depth are drawn, to correspond with the parallels on the land, which are drawn to coincide with the snow line; but it is evident they must be almost entirely imaginary.

As the equator appears to be the centre of organic vigour, from which the vivifying principle of heat extends to all parts of the organic world, so lines are drawn from an imaginary point (m) representing the equator, and on these lines the natural orders of plants and animals are marked; the lines being thickened (x) where the order is supposed to be most abundant. These lines being supposed movable, like the radii of a circle, are intended to point out by the space they would traverse in their imaginary motion, the district within VOL. II. No. 9.

A A