in the same manner to shut it; and this office they perform so exactly, that, in the living animal, the opening can scarcely be discerned, except when the sides are forcibly drawn asunder.* Is there any action in this part of the animal, any process arising from that action, by which these members could be formed? any account to be given of the formation, except design?

III. As a particularity, yet appertaining to more species than one, and also as strictly mechanical, we may notice a circumstance in the structure of the claws of certain birds. The middle claw of the heron and cormorant is toothed and notched like a saw. These birds are great fishers, and these notches assist them in holding their slip pery prey. The use is evident; but the structure such as cannot at all be accounted for by the effort of the animal, or the exercise of the part. Some other fishing birds have these notches in their bills; and for the same purpose. The gannet, or Soland goose, has the edges of its bill irregularly jagged, that it may hold its prey the faster. Nor can the structure in this, more than in the former case, arise from the manner of employing the part. The smooth surfaces, and soft flesh of fish, were less likely to notch the bills of birds, than

*Goldsmith's Natural History, vol. iv. p. 224.

†TAB. XXV. Fig. 1. The middle claw of the heron. Fig. 2. The head of the Soland goose, (pelicanus bassanus) drawn from a specimen in the Ashmolean Museum.

the hard bodies upon which many other species feed.

We now come to particularities strictly so called, as being limited to a single species of animal. Of these I shall take one from a quadruped and one from a bird.

I. The stomach of the camel is well known to retain large quantities of water, and to retain it unchanged for a considerable length of time.* This property qualifies it for living in the desert. Let us see, therefore, what is the internal organization, upon which a faculty so rare, and so beneficial, depends. A number of distinct sacks or bags (in a dromedary thirty of these have been counted) are observed to lie between the membranes of the second stomach, and to open into the stomach near the top by small square apertures. Through these orifices, after the stomach

* TAB. XXVI. exbibits the cells in the stomach of the camel, from a preparation in the museum of the Royal College of Surgeons, London. In the camel, dromedary, and lama, there are four stomachs, as in horned ruminants; but the structure, in some respects, differs from those of the latter. The camel tribe have in the first and second stomach numerous cells, several inches deep, formed by bands of muscular fibres crossing each other at right 'angles; these are constructed so as to retain the water, and completely exclude the food. In a camel dissected by Sir E. Home, the cells of the stomach were found to contain two gallons of water; but in consequence of the muscular contraction, which had taken place immediately after death, he was led to conclude this was a quantity much less than these cavities were capable of receiving in the living animal. See Lectures on Comparative Anatomy, by Sir E. Home, vol. i. p. 168.

is full, the annexed bags are filled from it; and the water so deposited is, in the first place, not liable to pass into the intestines; in the second place, is kept separate from the solid aliment; and, in the third place, is out of the reach of the digestive action of the stomach, or of mixture with the gastric juice. It appears probable, or rather certain, that the animal, by the conformation of its muscles, possesses the power of squeezing back this water from the adjacent bags into the stomach, whenever thirst excites it to put this power in action.

II. The tongue of the woodpecker is one of those singularities which nature presents us with when a singular purpose is to be answered. It is a particular instrument for a particular use: and what, except design, ever produces such? The woodpecker lives chiefly upon insects, lodged in the bodies of decayed or decaying trees. For the purpose of boring into the wood, it is furnished with a bill, straight, hard, angular, and sharp.* When, by means of this piercer, it has reached the cells of the insects, then comes the office of its tongue; which tongue is, first, of such a length that the bird can dart it out three or four inches from the bill,-in this respect differing greatly from every other species of bird; in the second place, it is tipped with a stiff, sharp, bony thorn; and in the third place, (which appears to me the most

* TAB. XXVII. Fig. 1. The head of the woodpecker, (picus viridis.)