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of hair is perhaps used to clean the teeth of the opTHE HOUSE SPIDER,
posite maxilla. PIDERS are not now ranked among insects;
because, as the handbooks of entomology state, "they have no antennæ, no division between the head and the thorax; they breathe by leaf-shaped gills situated under the belly instead of spiracles in the sides; have a heart connected with these; have eight legs instead of six, and six or eight fixed eyes.
With the exception of the dragon-fly, whose head is terribly armed, there is not, perhaps, another creature possessed of such a fearful array of weapons as the spider. These weapons form beautiful microscopic objects, and as such they deserve attention.
The house spider (Aranea domestica) has eight simple eyes; these are set in two rows in the upper part of the head, and beneath them are the two larger jaws or mandibles ; each of these mandibles contains a number of teeth, and is terminated by a large claw, a portion of the inner side of which is finely serrated. The number of teeth in a mandible is perhaps variable: there are eight in the specimens from which the figure given in this paper has been taken (fig. 2),
Fig. 3. Maxillæ of Spider. but sometimes five only have been found. The claws With the assistance of an ordinary pocket magnifyfrequently vary somewhat in the curvature of their ing glass the action of the mandibles may be disends, and are more finely pointed in some instances tinctly seen. It is a curious thing to watch a spider than in others.
making a repast of a fly; to see with what dexterity I have read somewhere that the action of these it uses each mandible alternately, as, with the claws is downward: this I have not been able to greatest ease, it turns the body of the fly round, and verify, for in the cases in which I have seen them in presses it until it becomes a shapeless mass of juicy action, they were nearly horizontal, having only a pulp. slight inclination downward; and in the cast skins The mandibles contain the poison, and the poison
duct may be traced to the extremity of the claw, if the latter be sufficiently bleached before mounting.
The rapidity and fatality of the action of the poison has frequently been a subject of remark; the following simple observation sets it in a clear light. A stout fly became entangled in the web of a spider : quick as lightning, out darts the spider and seizes the fly, and equally quick was the interference to the rescue; it was relieved and set at liberty, the fly then walked smartly up a window-pane, stopped awhile, brushed its wings with its hind feet, rubbed its feet, and dressed itself; this was the action of a minute. It then walked about again, apparently all right. Presently it stood without motion, and after a few seconds, when touched, it was found to be scarcely able to raise its feet, and after a few seconds more it was quite dead.
Much interesting matter relative to insects may
easily be obtained by the exercise of a little patient Fig. 2. Mandible of Spider.
and continued observation. The above has been to be found on old walls, the claws lie close to the written with the desire of calling the attention of the mandibles, and in a horizontal direction. Beneath general reader to a few of the wonderful things in the mandibles are the maxillæ (fig. 3), or smaller the common objects of nature, and pointing out to jaws, each of these contains a row of very fine teeth, the young microscopist two objects easily found and at the end of each row there is a thick tuft of upon which the first efforts at mounting may be hair. The teeth are so placed that in all probability successfully exercised. the two rows work against each other, and each tuft
LEWIS G. MILLS, LL.B., Armagh.
In a very rich piece of newly broken-up ground I gathered, a few years ago, some leaves of Dandelion (Fig. 4), which, owing to luxuriant growth, had become enormously large and much more deeply cut than usual, being, in fact, bi-runcinate. Leaves often become more deeply cut from porcrty, and more simple through luxuriance, but in this case the extra cutting was undoubtedly caused by the richness of the soil, there being several similar plants, each of which was nearly two feet across.
In another case, however, of Horse-radish (Fig. 5), the radical leaves of nearly all the plants in my garden became last year so deeply cut as to be almost pinnate. This was no doubt caused by the dryness of the season. The horse-radish is a plant which loves a cool, moist soil, establishing itself by the side of water, and in the half-dry beds of rivers, where it grows luxuriantly, and the continued drought impoverished the plants. It is quite the character of the order Crucifera to have pinnatifid or lyrate leaves, and it is somewhat remarkable that
Fig. 7. Figure 7 is a drawing of a not unfrequent form of Plantain (Plantago lanceolata), which has become proliferous, oducing small flower-heads on footstalks and several leaves from the base of the flower. Gathered at Beaumaris during the last
Fig. 8 is a very interesting example of Marvel of Whilst at Llanberis during the past summer, I found, Peru (Wirabilis jalapa), which has grown in my in the garden of the hotel where we were staying, a garden during the last summer. This plant belongs curious flower of Weigelia, very similar in its abto the natural order Nyctaginacea, a tribe in which normal development to a primrose which I described there is no corolla, but the calyx becomes coloured, and is placed, solitary or clustered, in an involucre
Fig. 9. a. normal; b. abnormal.
in No. 5 of SCIENCE-GOSSIP. There was a corolla of the usual shape and size, which contained only one perfect stamen, all the other internal organs being converted into a short branch, upon the base of which were placed two or three leaflike greenish bracts, and on the summit a second corolla, rather irregular in shape and containing half-developed stamens and pistil.
The flowers of the double-blossomed Cherry, which
are so great an ornament in our gardens in May, Fig. 8.
always show us some interesting examples of abof leafy bracts. In the case of the Marvel of Peru, normal development. The duplication of the flower however, no one would suppose, from merely looking is effected by the conversion of some of the numerous at the flower, but that there was a beautiful crimson stamens into petals, a considerable number of the staor yellow or streaked monopetalous corolla placed mens remaining still unchanged, so that if the pistils within an ordinary green calyx of five sepals. were perfect, there would be no reason why the Botanists tell us, however, that this corolla is no double-blossomed cherry should not always produce corolla at all, but a calyx, and that what we supposed fruit. to be calyx is only bracts. In the specimen figured, If the flowers be examined, however, the pistil two of these coloured perianths have grown within will be found to have suffered change, becoming, not one pseudo-calyx, showing that the latter organ is a new series of petals, but two little green leaves, really an involucre, and establishing the relationship folded one within the other, in the centre of the of this plant with Nyctago and other genera in which flower. Now and then the pistil remains perfect, the nature of the involucral leaves cannot be mis- and if it happen to be fertilized by the stamens it taken. Such specimens bave been observed before, grows, and we lo find occasionally one or two ripe and been made use of in proving the affinities of cherries on a tree. Last year I observed on a tree Mirabilis.
in my own garden, that in very many of the flowers I have several times noticed a curious variety of the two little central green leaves had become a the Common Columbine (Aquilegia rulgaris), which regular calyx enclosing a second double-flower. I think comes up the same year after
but The Poet's Narcissus (N. poeticus), which we in this point I am not sure. The flower of this variety Cheshire call by the pretty name of “Sweet Nancy,” is entirely destitute of the horn-shaped hollow petals is very curious in its manner of duplication. I have so characteristic of the plant, but their place is taken many patches of it, some of which are semi-double, by a second and often third ring of flat leaves, being either double ones reverting to single, or which are either altered petals or multiplied sepals, single ones becoming double, I know not which; and which give the flower very much the appearance and in these the way in which the flower becomes of the double form of Love-in-a-mist (Nigella), minus double may be well seen. A single flower consists the pectinated involucre. I made no drawing of this of six leaves united into a tube, around the mouth variety at the time, but the following outline from of which stands the crimson cup-shaped nectary, six memory will serve to explain it sufficiently (Fig. 9). stamens being attached to the sides of the tube.
If one of these semi-double flowers be examined, a dry one, such as we have had. But I am rather it will be found that each stamen has become, not inclined to think that I do see, last year, some little merely a new petal, but actually a new flower, for it difference in the character of the abnormal forms; forms a tube, the mouth of which consists of, on one that, whereas, in ordinary seasons, the tendency in side a crimson nectary, on the other a white petal monstrous flowers is a reversion to leaves ; this has (fig. 10, a), and frequently, attached to this nectary, not been so much the case during the dry, hot a bristle (fig. 10,6), which I take to be a rudimentary summer of 1865.
ROBERT HOLLAND. stamen. These six new petals do not unite like the outer petals of the flower, but are always distinct
VEGETABLE FIBRES. from each other; and if the flower becomes quite double, it is by a multiplication of these inner florets, AT a recent meeting of the Quekett Microscopical the change sometimes extending itself to the pistil, which separates into three unshapely petals.
the microscope to the discrimination of vegetable fibres. The object of this communication was to point out what had been done, and to suggest what remained to be accomplished, and the best mode of performing it. Although adulterations of food have been well cared for and deeply investigated, adulterations or admixtures in fabrics, whether of animal or vegetable origin, have hitherto obtained but little attention. Yet, it is urged, the subject is an important one and well deserving systematic research. All fibres employed for commercial purposes may be divided into four classes, two of which are animal-i.e., wool and silk--and two vegetable; which may be termed vascular and cellular.
WooL has a peculiar structure, readily to be distinguished from all other animal and vegetable fibres
(fig. 11,6), and differing slightly in its own varieties, Fig. 10. In the autumn my children brought me half-adozen double damsons which were all found on one tree. The old order Rosacea is, now-a-days, broken up into several minor orders, one of which is Drupacea, which is distinguished from Rosaceæ proper mainly by there being only one ovary in the flower instead of several, this one ovary becoming
6 eventually what we call a "stone fruit." If any plum tree be examined whilst in blossom, one can scarcely fail in finding a few flowers in which there are two, three, or more pistils and as many carpels, showing a tendency in the order Drupaceæ " to assume one of the distinguishing characters of Roseworts," as noticed by the late Dr. Lindley in his." Vegetable Kingdom" (Order Drupaceæ, p. 557). Generally, I think, these polygynous flowers drop off. Sometimes, no doubt, one carpel will come to maturity and the others will dwindle away, and we have only a one-celled fruit from several pistils,
Fig. 11.a. Cotton; b. Wool ; c. Silk. as is the rule in Cocoa-nuts, Hazel-nuts, and many as may be seen by reference to a paper on hairs in other plants. But occasionally all the pistils become our first volume. (Vol. i. p. 29.) Yet we have no fertilized, and the result is a compound fruit as in work of authority, and no reliable figures of the the present instance.
microscopic appearances of different qualities and More than one botanical friend has remarked to classes of wool, even of those ordinarily met with in me upon the prevalence of monstrous forms of commerce. It must be possible to characterize miflowers during the past summer. As far as my own croscopic features whereby Saxony can be distinexperience goes, I have not found them more plenti- guished from South-down, and Australian from East ful than usual ; indeed, I think that a wet season is Indian. generally more productive of abnormal growth than SILK (fig. 11, c) is more uniform in its character, and the difficulty would be greater to point out the country or climate of production. It is natural to features which distinguish the produce of the mul- inquire whether the microscope can detect differences berry worm from that of the Tusseh of India, the between Irish and Belgian, or between Egyptian and Moonga or Erie of Assam, and the Ailante of recent Spanish flax. In 1860, Dr. Forbes Watson comintroduction into Europe.
municated an important paper to the Society of Vegetable fibres of the cellular kind are hairs Arts, in which the microscopic character of vegewhich invest the seeds of certain plants, COTTON table fibres received more attention than had ever being of the chief importance (fig. 11, a). This has before been given to the subject, and since that been described as a flat band with thickened margins, period nothing has been attempted in advance. The and a delicate tracery down the centre; much woodcuts used to illustrate these observations were twisted throughout its length. This may appear to prepared for that occasion, and have been kindly be the structure on a superficial examination of the placed at our disposal by Dr. Watson. The microdried cotton, but the normal structure is certainly scopic characters we are about to give are those that of a cylindrical hair with thin walls, readily which then accompanied the illustrations, collapsing and twisting as it becomes dry, its ap- The flax fibre (lig. 13, a) presents at varying disparent margin being formed by incomplete compres- tances certain characteristic cross markings, the sion and the resistance at the edges as seen in the outlines of the fibres are hard and smooth, and the following section of a fresh( fig. 12, a) and dried hair ultimate fibrillæ can seldom be detected until carc. (6). The supposed tracery is an optical illusion, fully detached from the ordinary fibres.
A strong fibre is obtained from the Chinese nettle, or Rhea (see S. Gos., vol. i. p. 277), known botanically as Boehmeria nivea, and sometimes called
China-grass. Under the microscope its fibres present Fig. 12.
a peculiarly rough appearance, and when viewed by caused by the irregular wrinkling of the two oppo- reflected light have an appearance not unlike frosted site walls when in contact. Very important investi- grass. gations on this subject have been commeneed in Another Indian nettle, called the NEILGHERRY Manchester. Are there really any distinguishable NETTLE (Urtica heterophylla), of which a figure has microscopic differences between Sea Island and already becn given (vol. i. p. 276), yields a similar Egyptian, New Orleans and African, or between but more woolly fibre. (Fig. 14, 6.) Under the Brazilian and Surat ?
Vascular fibres are derived either from the inner bark (liber) of exogenous or the vascular bundles of the leaves of endogenous plants. Each of these groups would possess their own peculiar features.
Fig. 14. a. Chinese nettle; 6. Neilgherry nettle; c. Bedolee.
microscope it exhibits considerably greater asperities than the Rhea, and has been recommended as a substitute or for admixture with wool. A comparison of the two figures (fig. 11, b, and fig. 14, 6) will prove that such an admixture could readily be detected.
The fibre of the MUDAR (Calotropis procera) is similar in commercial value, but characteristically
The most important of liber-fibres is Flax, obtained from the common flax plant (Linum usitatissimum). This possesses a variable market value according to