tradict each other than he can contradict himself.

But let me endeavour to emerge from this ocean in which I seem to have lost myself, and, recovering my station upon terra firma, direct the attention of the reader to the lovely tribes that adorn every part and portion of this our destined but brief abode, I mean to the vegetable kingdom; we see how they cover earth, that not a spot can be found, of which in time they do not possess themselves, and that the more we extend our inquiries the more numerous are the individual species with which we become acquainted. This being the case upon earth, reasoning from analogy, we may conclude that something similar takes place in the ocean; that could our discoveries be extended under the sea as easily as they are upon land; could we traverse the bed and waters of the great deep with the same facility that we do the surface of the earth, we should find the numbers of vegetables that respire, in some sense, the air, fall short perhaps of those plant-like animals that respire the water. And could we examine the individual species of which this infinite host consists, and compare their organizations, we should find as great a difference in the instruments and organs by which their life is supported and their kind continued, as in the animals themselves; and yet in all this diversity should trace a harmony and

concatenation that would evidently prove the Wisdom that contrived, the Power that formed, and the Goodness that gave a living principle and breath of life to all these creatures, were each of them the attributes of an INFINITE BEING.

CHAPTER VIII.

Functions and Instincts. Bivalve Molluscans.

HITHERTO in our progress from the lowest animals upwards, the mind has been perpetually submerged; not only every group, but every individual that we have had occasion to consider, has been an inhabitant of the waters, and to the great body of which a fluid medium is as necessary to life and action as an aërial one is to a land animal, but now we shall be permitted to emerge occasionally, for although the largest proportion of the animals forming the great class we are now to advert to, the Molluscans, are also aquatic, yet still a very considerable number of them are terrestrial, as a stroll abroad will soon convince us, when after a shower we find we can scarcely set a step without crushing a snail or a slug.

2

The term Molluscan' was employed by Linné to designate his second class of worms, which excluded all the shell-fish, and amongst real Molluscans included both Radiaries, Tunicaries, and Worms; it literally signifies a nut or walnut, and therefore seems more properly applied to shell-fish, than to animals which are defined as simple and naked. As now understood, it still comprehends a very wide range of animal forms, and it seems difficult to describe them by any character common to them all. Their Almighty Author, in the progress of his work of creation, linked form to form in various ways; he not only made an animal of a lower grade a steppingstone towards one of a higher, and which formed a part of the ascent to man, the highest of all; but as the mighty work proceeded, he threw out on each side collateral forms that ascend by a different route, or begin one to a different order of beings. And this circumstance it is that has opened the door for so many systems and that diversity of sentiment with respect to the grouping of animals, which we meet with in the writings of the most eminent naturalists. Some proceed by one path and some by another, though the object of all is the same, unless some bias from a favourite hypothesis interferes and diverts them from a right judgment.

1

The organization of the animals of the Class

1 Mollusca.

2 Vermes.

we have just left, as we have seen, appears of a higher character than that of any of the preceding ones; traces of a heart appear; a nervous ganglion is detected between the mouth and anus, sending nerves to each; a regular respiratory system by means of gills becomes evident; but still the animal is furnished with no head, no eyes, and in numerous cases has no separate existence, but forms a branch of the general body-thus resembling a plant-from which it cannot dissociate itself and become an independent individual.

3

Indeed when we enter the Class of Molluscans, we find that the nearest affinities of the Tunicaries have likewise no head, and this circumstance appears to have induced Lamarck not only to separate them from the class as arranged by Cuvier, but also his whole family of headless Molluscans,' of which he forms his two Classes of Cirripedes and Conchifers. The absence of a head from the animals of the bivalve and multivalve shells, is certainly a circumstance which, at the first blush, appears to justify their separation classically from the other Molluscans, but when we compare other characters, we shall find many that are common to both, particularly their nervous system, which is the same both in the Conchifers and Molluscans of Lamarck; for neither of these exhibit

a medullary ganglionic chord, but only dispersed ganglions which send forth the requisite nerves; both have a double or bilobed mantle, gills on each side, and a heart and circulation. The Cirripedes indeed seem to be of a higher grade, at least their nervous system is more perfect-since they have a longitudinal spinal marrow with ganglions, a mouth furnished with toothed jaws disposed by pairs, and jointed tendril-like organs about the mouth-and approaches near to that of the Annulose animals,1 the Condylopes of Latreille. These, therefore, may be considered as properly entitled to the denomination of a Class; but should not be placed at a distance from the Crustaceans, to which Lamarck, with reason, thinks they make a near approach, as they are by Cuvier and Carus. In fact, they seem to have little to do with the bivalve Molluscans, except in being defended by more than one shell, and having no head.

I shall now mention the most prominent characters of those shell-fish, that I regard as strictly entitled to the denomination of Molluscans.

ANIMAL Soft, without articulations. Mantle bilobed, enveloping more or less the animal. Gills varying. A heart and circulation. No medullary chord with ganglions, but a few scattered ganglions from which issue nerves to various

1 Annulosa.