great sections, viz. herbivorous and carnivorous; the carnivorous are also divisible into two families of different office, the one attacking and destroying living bodies, the other eating dead bodies that have perished in the course of nature, or from accidental causes; after the manner of those species of predaceous beasts and birds, e. g. the Hyænas and Vultures, which, by preference, live on carrion. The same principle of economy in nature, which causes the dead carcasses of the hosts of terrestrial herbivorous animals to be accelerated in their decomposition, by forming the food of numerous carnivora, appears also to have been applied to the submarine inhabitants of the most ancient, as well as of the existing seas; thus converting the death of one tribe into the nutriment and support of life in others.

It is stated by Mr. Dillwyn, in a paper read before the Royal Society, June 1823, that Pliny has remarked that the animal which was supposed to yield the Tyrean die, obtained its food by boring into other shells by means of an elongated tongue; and Lamarck says, that all those Mollusks whose shells have a notch or canal at the base of their aperture, are furnished with a similar power of boring, by means of a retractile proboscis.* In his arrangement of inverte

the manner in which they have the principal viscera packed within the spiral shell.

* The proboscis, by means of which these animals are enabled to drill holes through shells, is armed with a number of minute teeth, set like the teeth of a file, upon a retractile membrane, which the animal is enabled to fix in a position adapted for boring or filing a hole from without, through the substance of shells, and through this hole to extract and feed upon the juices of the body within them. A familiar example of this organ may be seen in the retractile proboscis of Buccinum Lapillus, and Buccinum Undatum, the common whelks of our own shores. A valuable Paper on this subject has recently been published by Mr. Osler (Phil. Trans., 1832, Part 2, P. 497,) in which he gives an engraved figure of the tongue of the Buccinum Undatum, covered with its rasp, whereby it perforates the shells of animals destined to become its prey. Mr. Osler modifies the rule or the distinction between the shells of carnivora and herbivora, by showing that, although it is true that all beaked shells in

brate animals, they form a section of the Trachelipods, which he calls carnivorous. (Zoophages.) In the other section of Trachelipods, which he calls herbivorous (Phytiphages) the aperture of the shell is entire, and the animals have jaws formed for feeding on vegetables.

Mr. Dillwyn farther asserts, that every fossil Turbinated Univalve of the older beds, from the Transition lime to the Lias, belongs to the herbivorous genera; and that the herbivorous class extends through every stratum in the entire series of geological formations, and still retains its place among the inhabitants of our existing seas. On the other hand, the shells of marine carnivorous Univalves are very abundant in the Tertiary strata above the Chalk, but are extremely rare in the Secondary strata, from the Chalk downwards to the Inferior oolite; beneath which no trace of them has yet been found.

Most collectors have seen upon the sea shore numbers of dead shells, in which small circular holes have been bored by the predaceous tribes, for the purpose of feeding upon the bodies of the animals contained within them; similar holes occur in many fossil shells of the Tertiary strata, wherein the shells of carnivorous Trachelipods also abound; but perforations of this kind are extremely rare in the fossil shells of any older formation. In the Green-sand and Oolite, they have been noticed only in those few cases where they are accompanied by the shells of equally rare carnivorous Mollusks; and in the Lias, and strata below it, there are neither perforations, nor any shells having the notched mouth peculiar to perforating carnivorous species.

It should seem, from these facts, that in the economy of submarine life, the great family of carnivorous Trachelipods, performed the same necessary office during the Tertiary period, which is alotted to them in the present ocean. We

dicate their molluscous inhabitant to have been carnivorous, an entire aper. ture does not always indicate a herbivorous character.

have farther evidence to show, that in times anterior to, and during the deposition of the Chalk, the same important functions were consigned to other carnivorous Mollusks, viz. the Testaceous Cephalopods ;* these are of comparatively rare occurrence in the Tertiary strata, and in our modern seas; but, throughout the Secondary and Transition formations, where carnivorous Trachelipods are either wholly wanting, or extremely scarce, we find abundant remains of carnivorous Cephalopods, consisting of the chambered shells of Nautili and Ammonites, and many kindred extinct genera of polythalamous shells of extraordinary beauty. The Molluscous inhabitants of all these chambered shells, probably possessed the voracious habits of the modern Cuttle Fish, and by feeding like them upon young Testacea and Crustacea, restricted the excessive increase of animal life at the bottom of the more ancient seas. Their sudden and nearly total. disappearance at the commencement of the Tertiary era, would have caused a blank in the "police of nature," allowing the herbivorous tribes to increase to an excess, that would ultimately have been destructive of marine vegetation, as well as of themselves, had they not been replaced by a different order of carnivorous creatures, destined to perform in another manner, the office which the inhabitants of Ammonites and various extinct genera of chambered shells then ceased to discharge. From that time onwards, we have evidence of the abundance of carnivorous Trachelipodes, and we see good reason to adopt the conclusion of Mr. Dillwyn, that "in the formations above the Chalk, the vast and sudden decrease of one predaceous tribe has been provided for by the creation of many new genera, and species, possessed of similar appetencies, and yet formed for obtaining their prey by habits entirely different from those of the Cephalopods."+

* See explanation of the term Cephalopod, in note at p. 230.

+ Mr. Dillwyn observes farther, that all the herbivorous marine Cepha

The design of the Creator seems at all times to have been, to fill the waters of the seas, and cover the surface of the earth with the greatest possible amount of organized beings enjoying life; and the same expedient of adapting the vegetable kingdom to become the basis of the life of animals, and of multiplying largely the amount of animal existence by the addition of Carnivora to the Herbivora, appears to have prevailed from the first commencement of organic life unto the present hour.

Mr. De la Beche has recently published a list of the specific gravities of living shells of different genera, from which he shows that their weight and strength are varied in ac commodation to the habits and habitation of the animals by which they are respectively constructed; and points out evidence of design, such as we discover, in all carefully conducted investigations of the works of nature, whether among the existing or extinct forms of the animal creation.*

lopods of the Transition and Secondary strata were furnished with an operculum, as if to protect them against the carnivorous Cephalopods which then prevailed abundantly; but that in the Tertiary formations, numerous herbivorous genera appear, which are not furnished with opercula, as if no longer requiring the protection of such a shield, after the extinction of the Ammonites and of many cognate genera of carnivorous Trachelipods, at the termination of the Secondary period, i. e. after the deposition of the Chalk formation.

* "It can scarcely escape the observation of the reader, that, while the specific gravities of the land shells enumerated are generally greatest, the densities of the floating marine shells are much the smallest. The design of the difference is obvious: The land shells have to contend with all changes of climate, and to resist the action of the atmosphere, while, at the same time, they are thin for the purpose of easy transport, their density is therefore greatest. The Argonaut, Nautilus, and creatures of the like habits require as light shells as may be consistent with the requisite strength; the relative specific gravity of such shells is consequently small. The greatest observed density was that of a Helix, the smallest, that of an Argonaut. The shell of the Ianthina, a floating Molluscous creature, is among the smallest densities. The specific gravity of all the land shells examined was greater than that of Carara marble; in general more approaching to Arragonite. The fresh-water and marine shells, with the exception of the VOL. I.-20

SECTION II.

FOSSIL REMAINS OF NAKED MOLLUSKS, PENS, AND INK-BAGS OF LOLIGO.

It is well known that the common Cuttle Fish, and other living species of Cephalopods,* which have no external shell, are protected from their enemies by a peculiar internal provision, consisting of a bladder-shaped sac, containing a black and viscid ink, the ejection of which defends them, by rendering opaque the water in which they thus become concealed. The most familiar examples of this contrivance are found in the Sepia vulgaris, and Loligo of our own seas. (See Pl. 28, Fig. 1.)

It was hardly to be expected that we should find, amid the petrified remains of animals of the ancient world, (remains which have been buried for countless centuries in the deep foundations of the earth,) traces of so delicate a fluid as the ink which was contained within the bodies of extinct species of Cephalopods, that perished at periods so incalculably remote; yet the preservation of this substance is esta

Argonaut, Nautilus, Ianthina, Lithodomus, Haliotis, and great radiated crystalline Teredo from the East Indies, exceeded Carara marble in density. This marble and the Haliotis are of equal specific gravities.”—De la Beche's Geological Researches, 1834, p. 76.

* The figure of the common Calmar, or Squid (Loligo Vulgaris Lam. -Sepia loligo of Linnæus,) see Pl. 28, Fig. 1, illustrates the origin of the term Cephalopod, a term applied to a large family of molluscous animals, from the fact of their feet being placed around their heads. The feet are lined internally with ranges of horny cups, or suckers, by which the animal seizes on its prey, and adheres to extraneous bodies. The mouth, in form and substance resembles a Parrot's beak, and is surrounded by the feet. By means of these feet and suckers the Sepia octopus, or common Poulpe (the Polypus of the ancients,) crawls with its head downwards, along the bottom of the sea.