posed to yield the Tyrian dye, 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 invertebrate 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 further asserts, that every fossil Turbinated Univalve of the older beds, from the

* 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 shewing that, although it is true that all beaked shells indicate their molluscous inhabitant to have been carnivorous, an entire aperture does not always indicate an herbivorous character.

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

Mr. De la Beche has recently published a list of the specific gravities of living shells of different genera, from which he shews that their weight and strength are varied in accommodation 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.*

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 is 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 freshwater and marine shells, with the exception of the 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.

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

*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.

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 established beyond the possibility of doubt, by the recent discovery of numerous specimens in the Lias of Lyme Regis, in which the ink-bags are preserved in a fossil state, still distended, as when they formed parts of the organization of living bodies, and retaining the same juxta-position to a horny pen, which the ink-bag of the existing Loligo bears to the pen within the body of that animal. (Pl. 28, Fig. 1.)

*

Having before us the fact of the preservation of this fossil ink, we find a ready explanation of it, in the indestructible nature of the carbon of which it was chiefly composed. Cuvier describes the ink of the recent Cuttle Fish, as being a dense fluid of the consistence of pap, "bouillie," suspended in the cells of a thin net-work that pervades the interior of the ink-bag; it very much resembles common printers' ink. A substance of this nature would readily be trans

We owe this discovery to the industry and skill of Miss Mary Anning, to whom the scientific world is largely indebted, for having brought to light so many interesting remains of fossil Reptiles from the Lias at Lyme Regis.