meter, and the intestine afterwards continues nearly of that size.

In the long-legged casowary from New South Wales, the solvent glands are of the same length as those of the Emu, but are twice the width; they occupy the whole surface of the cardiac cavity, in the middle line of which there is a row of these glands in the direction of the cavity, and on the two sides the glands are arranged in an oblique direction towards this line. The gizzard is rather stronger than in the Emu, but resembles it in all other respects. The duodenum at its origin is by no means so large.

The annexed drawings (See Plates IV. V.) shew all the parts in so distinct a manner, as to make a more particular description of them unnecessary; and I feel myself much indebted to the kindness of Mr. HowSHIP, who, in the absence of Mr. CLIFT, took the trouble of making them. His knowledge of comparative anatomy has enabled him to execute them in a much more satisfactory manner than could have been done by any artist who was not at the same time an anatomist.

It is a very interesting part of comparative anatomy to examine the digestive organs belonging to birds, between which there is a similarity in size, food, and habits of life; and to trace the varieties in structure by means of which each species is enabled to subsist upon the produce of the country, of which it is the natural inhabitant, with every possible advantage. This cannot be better illustrated than by the following examples.

The Casuarius Emu, a native of Java, one of the most fertile and luxuriant islands in the world, has the solvent glands

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Sir E. HOME's Description of the solvent Glands, &c.

of a very small size; the gizzard so situated as only to be used occasionally; the small intestines five feet long, two inches in diameter, and the great intestine one foot long, making in all six feet; and two cæca, each of them six inches in length, onefourth of an inch in diameter. The Casowary of New South Wales, a less fertile country than Java, has larger solvent glands, a stronger gizzard placed under the same circumstances; the small intestines one inch and a quarter in diameter and ten feet seven inches long; the large, two inches in diameter, thirteen inches long, in all thirteen feet; the cæca two inches long, and half an inch in diameter.

The Rhea Americana, a native of South America, where its food is not abundant, has solvent glands of an unusually complex form, and a strong gizzard, so placed that every part of the food must be triturated in it. The small intestines one inch in diameter, ten feet seven inches long; the large intestine one inch and a quarter in diameter, one foot eight inches long, in all twelve feet three inches; but to these are added two cæca, each of them three feet ten inches, and two inches in diameter at the widest part.

The Struthio Camelus of Africa, which in the Desert has a very precarious subsistence, has solvent glands of the same structure as in the Rhea Americana, but much more numerous; a much stronger gizzard, so situated that the food must undergo a previous trituration before it can arrive at it; the small intestines one inch and a half in diameter, and twentyseven feet long; the large intestine two inches in diameter, and forty-five feet three inches long, in all seventy-two feet three inches; and two cæca three inches in diameter at the widest part, and each two feet nine inches long.