importance in itself, and helping to illustrate the need there is for rigorous scepticism and extended observation, on the part of zoological students. So long as we unsuspectingly accept what is repeated in books, without being assured that the statements are made on sufficient evidence, and so long as we have eyes but observe not, zoological progress will necessarily be slow, in spite of the vast number of excellent observers and workers who do accelerate our progress by genuine work. When I insist on the necessity for circumspect doubt, and verified observation, the reader must not understand me as implying that this necessity is not vividly present to the mind of many zoologists, and of every real worker; for in truth, only by such methods can any solid result be reached, and no one even superficially acquainted with the present state of zoology will be disposed to underrate the importance and extent of that band of distinguished investigators whose researches daily unfold fresh discoveries. Not, therefore, as throwing any shadow of scorn on these men and their methods; nor as if I were bringing a neglected principle into prominence, am I tempted to insist on the only method of successful pursuit in these studies; but simply to distinguish by it the students of zoology who wish to increase the circle of knowledge by some small addition of new fact, from students who wish merely to ascertain what is known. In zoology, as in all other departments of intellectual. activity, there are men contented with "information," whose ambition never passes beyond erudition. They want to know what is known. Others there are who, less solicitous, it may be, about what is known, are intensely moved to know for themselves; and these are the workers who extend the circle of the known.

What is known of the reproductive system of anemones? Not much, and that little confusedly. The text-books are somewhat precise; but the precision is for the most part that of error. I carried with me to the coast this amount of definite error, which gradually revealed itself as error in the course

of a series of investigations. That the reader may follow clearly the course of reasoning presently to be traced, it is necessary to begin with a few explanations which the better instructed will pardon. Let us first fix in our minds a definite idea of the structure of the anemone, as far as it will be involved in the subsequent remarks. Imagine a glove expanded into a perfect cylinder by air, the thumb being removed, and the fingers encircling, in two or three rows, the summit of the cylinder, while at the base the glove is closed by a flat surface of leather. If now on that disc which lies within the circle of fingers we press the head of a pencil-case, and so force the elastic leather to fold inwards, and form a sort of sac suspended in the cylinder, we have by this means made a mouth and stomach; we then cut a small hole at the bottom of the sac, and thus make a free communication with the general cavity. We then divide this general cavity by numerous partitions of card attached to the wall of the cavity, and form a number of separate chambers called the interseptal spaces. Just as the cavity of the finger is continuous with the cavity of the glove, so are the cavities of the tentacles continuous with the interseptal spaces. In these spaces will be found long coils of delicate membrane, which are sometimes seen lolling out of the mouth, and always bulge out when the anemone is cut open; these are called the convoluted bands, and to them attention is particularly directed. If the reader will now look at the diagram in Mr. Tugwell's Manual (Plate II., fig. 4), in Rymer Jones, or indeed in any modern work on zoophytes (wrong as these diagrams are in several details) he will have a tolerably accurate conception of the general structure of an Actinia.

Certain general facts must now be borne in mind. First, let me call attention to the fact that in all animals, the highest as the lowest, the envelope is of eminent importance, its predominance bearing a precise ratio to the simplicity of the organism. The simplest organisms breathe, exhale, secrete, absorb, and reproduce by their envelopes alone; and if the

more complex organisms perform each of these functions by a special apparatus of organs, yet these organs themselves are originally developed from the envelope. We may, ideally, reduce even a mammal to a cylindrical envelope folded inwards at each end; from the enfolded skin are developed all nutritive and reproductive organs, while the nervous system and its osseous sheaths are developed in the space between the outer and inner walls of the envelope. Thus every advance in complexity of organisation takes place through a gradual differentiation, or specialisation, of the general envelope. These important synonyms, differentiation and specialisation, I will explain by illustrating the law to which they point, namely, the law of animal development first enunciated by Goethe, and strikingly applied by Von Baer: Derelopment is always from the general to the particular, from the homogeneous to the heterogeneous, from the simple to the complex; and this by a gradual series of differentiations. When we say an organ has been formed out of a tissue, we say a differentiation has taken place; and the function, e. g. respiration, which before was performed by the general tissue, is now specialised, i. e. performed by that special organ. A homogeneous mass of organic matter, such as the Amoeba, which has no organ whatever, performs all the functions of assimilation, respiration, progression, and reproduction, by its general mass, not by any special organs. The process of differentiation by which special organs are gradually developed in the ascending scale of the animal series, is equally exhibited in any particular case of development. Thus if we follow the formation of the human hand, we find first a differentiation between the carpus or wrist, and the metacarpus or hand; next the fingers are differentiated, but, without any division into separate segments-this takes place later; then we have a separation between the soft and hard parts, the cartilage separating from the plastic mass; then these cartilages become osseous; and in the soft plastic mass we distinguish differentiations into muscle, tendon, skin, &c.; when the single

tissues are thus separated we may begin to trace differentiations in the skin, such as the papillæ, the secreting glands, and so forth: till, from a homogeneous mass of cells, we have traced the development of that marvellous and complex structure, the human hand.

Applying this torch to the obscure question of the reproductive system of the anemones, it at once discloses to us that the anemone being of a very simple organisation, almost entirely envelope, we shall be wrong if we expect to find in it a high complexity of special organs. Anatomists, indeed, have often neglected such a consideration, and have worried themselves in the search after organs, which à priori we may decide were not likely to be present. They have sought for and "discovered" nerves and ganglia, each discoverer scornfully rejecting the alleged discovery of his predecessor, and declaring the nerves were in a totally different locality, while no one anatomist could find them anywhere after another. They have worried themselves about the respiration of the anemone, not perceiving that respiration, like circulation and other functions elsewhere dependent on a special apparatus, was here performed in a direct and general manner. They have not suspected that reproduction takes place in the anemone, much in the same way as in the freshwater polype - not in any special and permanent apparatus of organs, such as ovary, oviduct, &c., but by a temporary specialisation of the general envelope including an accumulation of germ-cells and sperm-cells. am aware that special organs called ovaries are described in all books, and that some writers describe an oviduct-which only exists in their imagination, for no duct of any kind is found. Of course, no philosophical à priori conclusion could be permitted to stand up in contradiction to observed fact; if the organs are there, it is of no use deductively establishing their non-existence. But are they there?

When I first commenced the investigation of anemones, I had no reason whatever to doubt the statement so generally and confidently

made, that the convoluted bands were the organs in question. At the end of the first week my doubts began. These convoluted bands contained no trace of ova, but instead thereof they contained vast quantities of those thread capsules which I then believed to be urticating cells. This was the last place in the world where one might expect to find offensive weapons; and misled by the belief in these cells, I was led to question the function of the convoluted bands. Questioning, of course, meant something more than supine doubt. I began on the 14th May to examine closely into the evidence, and on the 12th June I was fortunate enough to confirm all doubts by the discovery of the real ovaries (such as they are) in a large Crassicornis: here there were no thread capsules, but abundance of unmistakable ova, each with its "vesicle of Purkinje." The thrill of delight with which the assurance broke upon me may be conceived. After exploring several other anemones, to remove all lingering doubt, I hastened to communicate the discovery to my friend Mr. Tugwell, in whose presence I again displayed the organs. At that time I, of course, believed that the grapelike cluster in which the ova were lying, were true and permanent ovaries; but having since been frequently unable to detect them in adult specimens, and never in young specimens, I come to the conclusion that these ovaries are temporary organs, formed by an accumulation of germ-cells in various parts of the lining membrane of the envelope; that, in fact, they represent the first rudimentary state of what in higher animals becomes the special organ. This conclusion is, however, purely theoretical, and I will now state what any one may see, who examines an adult fresh from the rockpool or tank. With a rapid but not deep incision we lay open the envelope from the outside; the convoluted bands will bulge through the opening; but if we are vigilant and brush these aside, we shall perceive certain lobular or grapelike masses of darker colour, almost entirely hidden by these bands, but growing from the walls of the envelope. They are not situated

in any precise spot; near the base about the centre, and close to the disc, they may be found: nor are they in every interseptal space; sometimes we may make three or four incisions before detecting them. Once seen, they will easily be distinguished from the convoluted bands, although so difficult is it to remove them without at the same time removing some of the bands, that to this cause alone can I attribute the long continuance of the opinion that the bands were the true ovaries. For it should be observed that several writers have discovered the ova, and one at least (Spix) seems to have seen the ovaries; but that no one had clearly discriminated and described the organs, is evident in the confusion which our text-books exhibit on the topic. I believe I may not only claim the discovery, as having been made independently, and without any knowledge of what Spix had seen, but also as having for the first time discriminated both anatomically and physiologically the ovaries from the convoluted bands, so as to clear up all confusion. I am not even certain that Spix recognised the real organs, since he describes ducts opening into the stomach by several apertures, when in truth there are no ducts, and the aperture at the base of the stomach is one, not several. It is from Dr. Johnston's History of British Zoophytes (for a hasty reading of which I was indebted to Mr Tugwell, after I had made the discovery) that I gather what Spix said. He describes the ovaries "as forming several grapelike clusters situated in the interseptal spaces with ducts which open into the base of the stomach by several apertures, and hence the ova are presumed to gain their freedom by traversing the stomach and mouth. De Blainville doubts this, being led to believe it more probable that the oviducts may open into the labial rim as they do in the asteroid polypes." From this it appears that even if Spix detected the ovaries, he did not accurately discriminate them from the convoluted bands; he did not accurately describe their structure, for he speaks of ducts where no ducts exist; he did not understand their nature, as temporary specialisa