Ray Lankester

“ A refreshing cold air comes up from the icy torrent, whilst the heat of the sun diffuses the delicious resinous scent of the pine trees. Above the naked rock we see steep hill-sides covered with forest, and away above these again bare grass-slopes topped by cloud. ”

“ Thus the smoke which the smoker keeps for half a minute in his mouth is cooled and condensed, and reflects white light—is, in fact, a white cloud—when he puffs it out, and contrasts strongly with the blue cloud coming off from the burning tobacco at the lighted end of the cigar. ”

“ In Limulus (fig. 23) each ommatidium has a peculiar ganglion cell developed in a central position, whilst the ommatidium of the lateral eyelets of Scorpio shows small intermediate cells between the larger nerve-end cells. The structure of the lateral eye of Limulus was first described by Grenacher, and further and more accurately by Lankester and Bourne (5) and by Watase; that of Scorpio by Lankester and Bourne, who showed that the statements of von Graber were erroneous, and that the lateral eyes of Scorpio have a single cell-layered or “monostichous” ommatidium like that of Limulus. ”

“ I feel, indeed, that it is necessary to ask forbearance for my presumption in daring to treat of so many subjects in which I cannot claim to speak as an authority, but only as a younger brother full of fraternal pride and sympathy in the glorious achievements of the great experimentalists and discoverers of our day. ”

“ Truly enough, it is not a beauty called forth by natural selection. It is primordial; it is the beauty of great light itself. The response to its charm is felt by every living thing, even by the smallest green plant and the invisible animalcule, as it is by man himself. As I stand on the mountain-side we are all, from animalcule to man, sympathizing and uniting, as members of one great race, in our adoration of the sun. And in doing this we men are for the moment close to and in happy fellowship with our beautiful, though speechless, relatives who also live. ”

“ Whatever may have happened in past geological epochs, by force of great earth-movements which rapidly brought the adaptations of one continent into contact with the parasites of another, it is quite certain that man, proud man, ever since he has learnt to build a ship, and even before that, when he made up his mind to march aimlessly across continents till he could go no further, has played havoc with himself and all sorts of his fellow-beings by mixing up the products of one area with those of another. ”

“ The alchemist’s dream is, if not realised, at any rate justified. One element is actually under our eyes converted into another; the element radium decays into a gas which changes into another element, namely helium.
Radium, this wonder of wonders, was discovered owing to the study of the remarkable phosphorescence, as it is called—the glowing without heat—of glass vacuum-tubes through which electric currents are made to pass. ”

“ You may read any quantity of books, and you may be almost as ignorant as you were at starting, if you don't have, at the back of your minds, the change for words in definite images which can only be acquired through the operation of your observing faculties on the phenomena of Nature. ”

“ For more than thirty years a few workers, here and there, have been searching for this parasite and the means of suppressing the awful curse of which it is the instrument. It would have been discovered many years ago had greater value been set on the inquiries which lead to such discoveries by those who direct the public expenditure of civilized States. And now the complete suppression of this dire enemy of humanity is as plain and certain a piece of work to be at once accomplished as is the building of an ironclad. ”

“ Once we have gained the fundamental conceptions as to what is meant by a "species," we are able intelligently to consider innumerable facts of the most diverse kind as to their peculiar structure and colours, their number, localities, their interaction and dependence on other living things, their modifications for special modes of life, their isolation or their ubiquity. ”

“ A lull after victory, a lethargic contentment, has to some extent followed on the crowning triumphs of the great Nature-searchers whose days were numbered with the closing years of that nineteenth century which through them marks an epoch. No power has called on Man to arise and enter upon the possession of his kingdom—the ‘Regnum Hominis’ foreseen by Francis Bacon and pictured by him to an admiring but incredulous age with all the fervour and picturesque detail of which he was capable. ”

“ There is, in fact, continuity and healthy evolution in the realm of science. Whilst some onlookers have declared to the public that science is at an end, its possibilities exhausted, and but little of the hopes it raised realised, others have asserted on the contrary, that the new discoveries—such as those relating to the X-rays and to radium—are so inconsistent with previous knowledge as to shake the foundations of science, and to justify a belief in any and every absurdity of an unrestrained fancy. ”

“ It is definitely ascertained that many animals are thus born with distorted or defective eyes whose parents have not had their eyes submitted to any peculiar conditions. Supposing a number of some species of arthropod or fish to be swept into a cavern or to be carried from less to greater depths in the sea, those individuals with perfect eyes would follow the glimmer of light and eventually escape to the outer air or the shallower depths, leaving behind those with imperfect eyes to breed in the dark place. ”

“ More usually, by an infolding of the layer of cells in development, we get three layers under the lens; the front layer is the corneagen layer, and is separated by a membrane from the other two which, more or less, fuse and contain the nerve-end-cells (retinal layer) . ”

“ In such a desultory survey as that on which I have ventured, of Man's kingdom and its dangers, it occurs to me to mention another area upon which it seems urgent that the activities of nature-searchers should be immediately turned with increased power and number. The experimental study of his body and of that of animals has been carried far and with valuable results by inquiring Man. But singularly small attention has yet been given to the investigation of Man's mind as a natural phenomenon and one which can be better understood to the immense advantage of the race. ”

“ At the same time the prostomium and its appendages cease to be recognizable as distinct elements of the head. The brain no longer consists solely of the nerve-ganglion-mass proper to the prostomial lobe, as in Chaetopoda, but is a composite (syncerebrum) produced by the fusion of this and the nerve-ganglion-masses proper to the prosthomeres or segments which pass forwards, whilst their parapodia (= appendages) become converted into eye-stalks, and antennae, or more rarely grasping organs. ”

“ Further, it is pointed out by Korschelt and Heider that the hinder portion of the gut frequently acts in Arthropoda as an organ of nitrogenous excretion in the absence of any special excretory tubules, and that the production of such caeca from its surface in separate lines of descent does not involve any elaborate or unlikely process of growth. In other words, the Malpighian tubes of the terrestrial Arachnida are homoplastic with those of Hexapoda and Myriapoda, and not homogenetic with them. ”

“ EU-ARACHNIDA.—These start from highly developed and specialized aquatic branchiferous forms, exhibiting a prosoma with six pediform pairs of appendages, an intermediate prae-genital somite, a mesosoma of six somites bearing lamelliform pairs of appendages, and a metasoma of six somites devoid of appendages, and the last provided with a post-anal spine. Median eyes are present, which are monomeniscous, with distinct retinal and corneagenous cell-layers, and placed centrally on the prosoma. ”

“ It has been considered by them as proving that Limulus, in spite of all its special agreements with Scorpio (which, however, have scarcely been appreciated by the writers in question) , really belongs to the Crustacean line of descent, whilst Scorpio, by possessing Malpighian tubes, is declared to be unmistakably tied together with the other Arachnida to the tracheate Arthropods, the Hexapods, Diplopods, and Chilopods, which all possess Malpighian tubes. ”

“ PANTOPODA.—Nomomeristic Arachnids, in which the somites corresponding to mesosoma and metasoma have entirely aborted. The seventh, and sometimes the eighth, leg-bearing somite is present and has its leg-like appendages fully developed. Monomeniscous eyes with a double (really triple) cell-layer formed by invagination, as in the Eu-arachnida, are present The Pantopoda stand in the same relation to Limulus and Scorpio that Cyamus holds to the thoracostracous Crustacea. ”

“ The nature of the post-anal spine has been strangely misinterpreted by some writers. Owen (7) maintained that it represented a number of coalesced somites, regardless of its post-anal position and mode of development. The agreement of the grouping of the somites, of the form of the parapodia (appendages, limbs) in each region, of the position of the genital aperture and operculum, of the position and character of the eyes, and of the powerful post-anal spines not seen in other Arthropods, is very convincing as to the affinity of Limulus and Scorpio. ”

“ Die Phantasie ist ein unentbehrliches Gut; denn sie ist es, durch welche neue Combinationen zur Veranlassung wichtiger Entdeckungen gemacht werden. Die Kraft der Unterscheidung des isolirenden Verstandes sowohl, als der erweiternden und zum allgemeinen strebenden Phantasie sind dem Naturforscher in einem harmonischen Wechselwirken nothwendig. ”

“ The first segment of the mesosoma of Scorpio and Limulus thus remains the first segment, and can be identified as such throughout the Eu-arachnida, carrying as it always does the genital apertures. But it is necessary to remember, in the light of recent discoveries, that the sixth prosomatic pair of appendages is carried on the seventh somite of the whole series, there being two prosthomeres or somites in front of the mouth, the first carrying the eyes, the second the chelicerae ”

“ In the genus Nucula (fig. 10) we have an example of a Lamellibranch retaining this plume-like form of gill. In the Arcacea (e.g. Arca and Pectunculus) the lateral processes which are set on the axis of the ctenidium are not lamellae, but are slightly flattened, very long tubes or hollow filaments. These filaments are so fine and are set so closely together that they appear to form a continuous membrane until examined with a lens. ”

“ The nerve-end-cells, which lie below the lens, are part of the general epidermis. They show in the monomeniscous eye (see article Arachnida, fig. 26) a tendency to group themselves into “retinulae,” consisting of five to twelve cells united by vertical deposits of chitin (rhabdoms) . In the case of the polymeniscous eye (fig. 23, article Arachnida) a single retinula or group of nerve-end-cells is grouped beneath each associated lens. A further complication occurs in each of these two classes of eye. The monomeniscous eye is rarely provided with a single layer of cells beneath its lens ”

“ A brief notice must suffice of the structure and history of the Eyes, the Tracheae and the so-called Malpighian tubes of Arthropoda, though special importance attaches to each in regard to the determination of the affinities of the various animals included in this great sub-phylum.
The Eyes.—The Arthropod eye appears to be an organ of special character developed in the common ancestor of the Euarthropoda, and distinct from the Chaetopod eye, which is found only in the Onychophora where the true Arthropod eye is absent. ”

“ The structure of one is exhibited in fig. 20. A single otolith is present as in the veliger embryos of Opisthobranchia. In Filibranchia and many Protobranchia the otocyst (or statocyst) contains numerous particles (otoconia) . The organs are developed as invaginations of the epidermis of the foot, and in the majority of the Protobranchia the orifice of invagination remains open throughout life; this is also the case in Mytilus including the common mussel.
Anodonta has no eyes of any sort, and the tentacles on the mantle edge are limited to its posterior border. ”

“ The endopodite may be retained as a small segmented palp at the side of the gnathobase or disappear (mandible of Crustacea, Chilopoda and Hexapoda) .
(9) The corm becomes the seat of a development of a special visual organ, the Arthropod eye (as opposed to the Chaetopod eye) . Its jointing (segmentation) may be retained, but its rami disappear (Podophthalmous Crustacea) . Usually it becomes atrophied, leaving the eye as a sessile organ upon the prae-oral region of the body (the eye-stalk and sessile lateral eyes of Arthropoda generally, exclusive of Peripatus) . ”

“ The sexes are often, but not always, distinct. No accessory glands or copulatory organs are ever present in Lamellibranchs. The ctenidia often act as brood-pouches.
A dorsal contractile heart, with symmetrical right and left auricles receiving aerated blood from the ctenidia and mantle-skirt, is present, being unequally developed only in those few forms which are inequivalve. The typical pericardium is well developed. It, as in other Mollusca, is not a blood-space but develops from the coelom, and it communicates with the exterior by the pair of renal tubes. ”

“ In some Lamellibranchs (Pecten, Spondylus, Pholas, Mactra, Tellina, Pectunculus, Galeomma, &c.) , although cephalic eyes are generally absent, special eyes are developed on the free margin of the mantle-skirt, apparently by the modification of tentacles commonly found there. There are no pores in the foot or elsewhere in Lamellibranchia by which water can pass into and out of the vascular system, as formerly asserted.
The Lamellibranchia live chiefly in the sea, some in fresh waters. A very few have the power of swimming by opening and shutting the valves of the shell (Pecten, Lima) ”