MONTHLY 28 JUN 82 MUS MICROSCOPICAL JOURNAL VOL. III. Glass Cells. NEW YORK, JUNE, 1882. BY C. HENRY KAIN. Much has been said and written within the past year or two in regard to the proper material for cells, but in all the discussion I have noticed that very little mention is made of glass cells. For many purposes, especially for balsam or liquid mounts, they are preferable to all others, but their cost prevents their general use-a dollar a dozen being the usual price. I think if microscopists in general knew how easily they can be punched from glass covers, they would come into almost universal favor for shallow mounts. Their cost is trifling, as the cheaper grades of covers can be used, also those which would otherwise be thrown aside on account of some flaw or impurity in the centre. The following is the method of preparation Take a brass plate, say five inches long, one inch wide, and a quarter of an inch thick. Have a number of holes drilled (not punched) in it about an inch apart, and of various diameters corresponding to the diameters of the desired cells. See that in drilling these holes the shoulders are left perfectly square and sharp, but not burred. This is important, as the question of success or failure largely depends upon it. The plate having been thus prepared, heat it until it is sufficiently hot to melt a piece of sheet-wax placed upon it. Then place over each hole a disk of sheet-wax somewhat larger than the hole, and drop upon it a glass cover. The cover should be from of an inch to 4 of an inch larger in diameter than the hole. Press the No. 6. cover down so as to bring it in close contact with the metal plate, then set the plates away to cool. When perfectly cold take an ordinary sixpenny or eightpenny nail, boldly thrust it through the glass cover from the upper side, and rasp it round and round, always with a downward motion, until the cell appears perfectly circular. When all the covers upon the plate have been thus treated, reheat the plate so as to loosen the cells, throw them into benzine to dissolve the wax, let them remain a few minutes, then wipe them and put them away for use. The method given is simple, but when describing it I have sometimes been met with an incredulous smile, as the idea of punching holes in glass with an ordinary eightpenny nail seems so ridiculous. Nevertheless it is a successful method; and, furthermore, if the directions given. are carefully followed, not one cover in twenty need be spoiled in the process. Try it. [We have received some of the cells made by Prof. Kain by the method described above, but they were broken in the mail. Judging from the fragments, they were perfectly good cells for any and all purposes. If we are not mistaken, Dr. L. Beale describes a method quite similar, somewhere in his book on the microscope.-ED.] Rotifer Nests. Exploring ponds in the low grounds along Paxton creek, flowing through the eastern suburbs of the City of Harrisburgh, Pa., April 15th last, I was interested to find, besides a variety of species of Spirogyra, as decimina, fusco-atra, and Hantzschii, all in good fruiting condition, masses of Vaucheria geminata. On the filaments of this plant, nests of rotifers are of frequent occurrence. They appear as urn-shaped excrescences, cylindrical cells, outgrowths of the plant, somewhat swollen below the middle, contracted at the base, and distended at the truncate apex. Some are at the ends of the branchlets, eight to ten times the diameter of the branch, others grow out of the sides of the larger filaments; they measure 200 mm. to 350 mm. in diameter, about three times the thickness of the plant. In many of them the animals are seen, usually in motion in the lower part of the cells; all the cells contain many dull, rose-colored eggs. The cells are abnormal to the plant, and are probably produced by a sting or other irritation. Nest of this kind are unusual in my observations. I have seen the creature carrying its eggs have found rotifer eggs in vaucheria plants and know them to have occurred in the leaves of Sphagnum (bogmoss), but have not known their power to produce such uniform outgrowths for nests. F. WOLLE. A Remarkable New Rotifer. BY S. A. FORBES. GENUS Cupelopagis,* gen. nov. Footless, eyeless, without carapace, and totally destitute of cilia or other vibratile structures, or locomotor organs of any kind. The trochal disk has the form of a large, oblique cup, which can be either retracted wholly, or pushed up by a constriction of its FIG. 32.-Cupelopagis bucinedax, lateral view X 265. Drawn with camera lucida. a, cup; b, œsophagus; c, crop; d, mastax; e, stomach; f, vent; g, embryos; h, problematical, black, or dark-brown bodies, irregular in form and position, situated in the perivisceral cavity. at In a neglected aquarium in the Natural History Laboratory Normal, Ill., the glass became covered with a coating of algæ, among which swarmed stentors and several species of rotifers. The largest and most abundant of the latter is of a character so peculiar and remarkable as to merit description. wide mouth. In the bottom of this cup is the oral aperture, which opens into a very large, loose crop, at the bottom of which, and usually behind the middle of the body, is the mastax. The jaws, which project into the * Κτπελλον and παγτς. crop, are composed of two sharp, slender hooks, with about four slender, straight teeth at the inner base. The stomach is large, and the intestine very small and short, opening on the ventral surface of the body near the posterior end. C. bucinedax, sp. nov. The body is a coriaceous, flattened sac, minutely roughened over the whole surface, nearly as broad as long, and about three-fourths as thick. The dorsal outline is longest and strongly convex, the ventral being usually somewhat Concave. The cup is oblique, the ventral height being little more than half the dorsal. Its lower wall usually presents a shallow, longitudinal concavity, so that the aperture is slightly kidney-shaped. The surface of the cup is more delicately roughened than the body, and its edge is minutely erose. In an average specimen the length of the body, without the cup, was 0.16-in., and its width 0.014-in. This rotifer has no means of attracting its prey or bringing it within reach, but depends wholly on such animals as chance to swim into its oval cup. When a stentor or other animalcule of considerable size enters the trap, the rotifer quickly puckers up the aperture and contracts the walls of the cup upon it, until it is forced, with a sudden slip, into the ample cavity of the pharynx. This apparatus enables it to secure much larger prey than the usual ciliated structure; but, in the absence of locomotor organs, it can only live in water swarming with suitable food. In the aquarium mentioned it was living almost wholly on the large stentors. Measurement of the Power of Mr. W. H. Bulloch has devised a simple apparatus for measuring the magnifying power of oculars, which is illustrated in fig. 33. It consists of an ordinary microscope with an ob FIG. 33. jective of two inches equivalent focus, which, in practice, is the most satisfactory power for the purpose. This microscope is used to examine an image of a diaphragm, formed by the ocular to be measured. The exact size of the diaphragm and its distance from the ocular being known, the size of the miniature image formed by the ocular can be readily measured, and a simple calculation then gives the magnifying power. In the figure, AB represents the examining microscope; C is a stationary stage having a micrometer ruled in lines o.1 mm. apart. The tube with draw-tube, GD, carries the ocular to be tested at G, and the diaphragm of known size at D. The shape of the diaphragm-opening is shown at H, H'. By means of the drawtube the distance GD can be changed, but it is usually made ten inches from the diaphragm of the ocular to the end of the tube. The width of the aperture at D, in the instrument used by Mr. Bulloch, is 6.5 mm. Directing the instrument toward the light, an image of the aperture will be formed by the ocular, and can be focussed upon the micrometer at C. Then the size of the image can be read off in the microscope, and the difference between the size of the image and the actual size of the diaphragm indicates the power of the ocular. Suppose the image just covers eleven divisions on the micrometer, the distance being ten inches as above, then 65 divided by II is about 6, which is the magnifying power in diameters. A Bausch & Lomb periscopic oculer "C," measured in this way gave a power of 11 diameters; a Tolles 2inch solid, 161⁄2, and a Gundlach 4inch, 43. Pollen-tubes. About half a century ago, Amici observed that the pollen-grains produced tubular appendices by the absorption of moisture on the stigma, and came to the conclusion that these tubes descended from the stigma through the style to the placenta. Several other writers after him made the same observation, and further, brought the pollen-tubes in connection with the process of fertilization of the ovules. M. Brogniart was of the opinion that the pollen-tubes, after a shorter or longer penetration into the stigmatic tissues, expand on the accumulation in them of the contents of the pollen-grains, that the membrane of the tubes bursts, and the fovilla is thus scattered amongst the papillæ of the stigma. M. Tulasne stated, in 1849, that he had seen the end of the pollen-tube come in contact with the membranes of the embryo-sac, without producing there a depression or a strong adhesion. or The theory of the fertilization of the ovules by means of the tubular appendices of the pollen-grains descending through the style to the ovarian cavity, and thence seeking their way to the foramen of the ovules, is now universally adopted by authors, and, as it appears, mostly without personal examination observation; some of them attempt to explain the manner in which the pollen-tubes overcome the difficulties they find in their way towards the foramen. Lindley, in speaking of the fructification of the orthotropous ovules of the rockrose, states, on the authority of M. Brogniart, that the pollen-tube does not follow the placenta till it reaches the ovule, but quits the style at the top of the cavity of each cell, and thence lengthens in the open space inside the ovary till it reaches the foramen in the end of the ovules. Mr. Detmar has published more recently also a paper on the “Course of the Pollentubes," a synopsis of which was published in the April number of 1881 of the Journal of the Royal Microscopical Society, of London. I followed his description, having preparations of the ovaries of most of the plants he describes in my cabinet; his descriptions are correct, but I failed to detect any pollen-tubes on their way to the foramen. I am at a loss to account for my inability, after having dissected hundreds of ovaries in various stages of development, to observe in a single instance the entrance of a pollentube into the micropyle; for some time I attributed it to a want of skill in preparing my sections, but since I have had an opportunity to compare my preparations with some which, it is said, Hofmeister used as a basis for his descriptions, I came to the conclusion that this was not the cause it must be sought for somewhere else. At all events, it seems that the entrance of the pollen-tube into the foramen has been only observed in a few plants. Schacht, in his works, mentions: Canna, Viscum, Najas, Passiflora, and some geraniaceæ. I have examined these plants. In most of them the tubular appendices of the pollen-grains on the stigma are easily observable, but very soon they appear to discharge their contents in the conducting tissues of the style, and lose their existence as tubes. My observations on cactaceæ led me to believe that here I might meet with success, but I was disappointed again. I made a phyllocactus, commonly called "crab cactus," the subject of particular study, and as a result of my observations, I venture the following statement: The pollen-tubes insinuate themselves amongst the papilla of the stigma where, on bursting, the fovilla is taken up by the conducting tissue of the style. This tissue is composed of very fine fibrillæ, full of granular matter, whilst the process of fertilization is going on. At the base of the style, it spreads itself out over the walls of the ovary; it accompanies the vascular bundles in the funiculii from the placenta, up to their juncture with the ovules. The tuft of papillæ surrounding the mi cropyle of the anatropous ovule meets near the placenta the tuft of the conducting tissue of the funiculus, where the papillæ of the former absorbs, by endosmosis, the granular contents of the latter, and in this way I conceive that fertilization takes place. In the closed flower-bud of the same species of cactus, the stigma, as a matter of course, is yet free from pollen-grains and their appendices, but the conducting tissue is present in the style; it contains already a number of granules, different however from the granular matter present in the conducting tissue during the process of fertilization. The observations on crab cactus furnished me the data for a new theory of fertilization, and Cereus grandiflora (night-blooming cereus) furnishes data to arithmetically demonstrate the impossibility of fertilization of the vegetable ovules taking place, in the cactaceae at least, according to the old one. The specimen under investigation, gave the following data: Length of style, 9 inches (a hollow tube-inch in diameter). Ovarian cavity, a cylinder -inch in diameter, and over one inch in height. I made about forty transverse sections of the ovary, sufficiently thin to count 100 to the inch. Each section contained about thirty ovules, of which the greater number, however, floated off the knife, the funicules having been cut; the number of ovules in the ovary, would thus amount to at least 3,000. The style, in transverse sections, shows a ring of eighteen vascular bundles corresponding to the eighteen divisions of the stigma. Inside this ring is contained the conducting tissue, forming a hollow tube, the nature and compactness of which precludes the possibility of giving passage to 3,000 pollen-tubes. In the ovarian cavity there is also no room for 3,000 pollentubes, after they should have descend |