Spiraea

“ On a calm day you will rarely see one crawling on sand above low-water mark, for it is a place they do not choose by preference; those that are to be found there on the stormy day have lost their foothold, and have been washed about by the tide. Had they, like some other kinds of periwinkle, a sharp spire, how many would be the casualties under these circumstances! But as it is, you do not see a single specimen with a broken top: the rounded spire is an adaptation to circumstances, required for the protection of the tenant of the shell. ”

“ A quite peculiar form of spiral growth is produced in Spironium, in which the direction of growth in both lateral wings of the transverse girdle is inverse from the beginning. The left wing grows against the posterior, the right wing against the anterior pole of the principal axis, turning around it in crossed, eight-like spirals. The whole shell afterwards assumes a lentelliptical form.
Commonly between the embracing spiral turnings or convolutions a great number of radial beams is developed, irregularly disposed and often branching ”

“ In counting the whorls of which the spire consists, we commence at the apex, and reckon downwards to the last, or body whorl. The spire is described as being long or short in relation to the aperture: in which case, all that is above the aperture is measured with the spire. Its apex requires particular notice, as the character of the whole shell frequently depends upon the particulars observable in this part. It is sometimes obtuse, or blunt; sometimes acute, or sharp. ”

“ An extinct genus of ferns.
SPICULA (Lat. spicidum, a point) . Pointed needle-shaped bodies.
SPIRIFERA (Lat. spira, a spire or coil; fero, I carry) . An extinct genus of Brachiopods, with large spiral supports for the "arms."
SPIRORBIS (Lat. spira, a spire; orbis, a circle) . A genus of tube-inhabiting Annelides, in which the shelly tube is coiled into a spiral disc.
SPONGIDA (Gr. spoggos, a sponge) . The division of Protozoa commonly known as sponges.
STALACTITES (Gr. stalasso, I drop) . Icicle-like encrustations and deposits of lime, which hang from the roof of caverns in limestone. ”

“ At any rate there is no evidence that the shell of Spirula has lost a rostrum and a proöstracum; its characters must be regarded as primitive, not secondary. In the characters of the protoconch and of the commencement of the siphuncle, the shell of Spirula agrees with that of the Ammonoids, and in both its position is ventral, although in most Ammonoids the shell being exogastric the ventral side is the convex or external, while in Spirula the shell is endogastric and the siphuncle internal. The fact that the shell is not completely enclosed by the mantle is also a primitive character. ”

“ Less numerous but not less markedly in situ are the shells of productus and spirifer, the former with its finely-striated surface fresh as if the creature had died but yesterday, while the slender spines with which it was armed lie strewed around. In short, the whole suite of organisms points to a period of tranquil deposition in a sea of probably no great depth, where the lower forms of the animal kingdom flourished in abundance, contributing by their calcareous secretions to form continuous layers of limestone. ”

“ A genus of microscopic Foraminifera.
SPIRORBIS. Lam. A genus composed of species of Serpula, Auct. which are coiled round in a spiral disc like a snake at rest. S. nautiloides, fig. 5, is the common little white shell, found upon the shell of lobsters.
SPIRULA. (Spira, a winding compass.) Fam. Lituolata, Lam. Lituacea, Bl.—Descr. Convolute, smooth, symmetrical, discoid, with parallel unconnected whorls, divided into numerous chambers by transverse septa; siphon continuous.—Obs. This pretty little shell is partly internal, only a part of it being visible when on the animal. Fig. ”

“ Suborder I. Spiraeoideae is characterized by a flat or slightly concave receptacle on which the carpels, frequently five in number, form a central whorl; each ovary contains several ovules, and the fruit is a follicle. There are five sepals, five petals and the stamens vary from ten to indefinite. The plants are generally shrubs with simple or compound leaves and racemes or panicles of numerous small white, rose or purple flowers. This suborder, which is nearly allied to the order Saxifragaceae, contains 17 genera, chiefly north temperate in distribution. ”

“ To explain: everybody knows Spirea callosa to be a strong growing shrub, having umbels of rosy-colored flowers and strong, stout roots; the white flowered variety is quite dwarf, is more leafy and bushy than the species, and has more fibrous and delicate roots than the type; the crisp-leaved variety is still more dwarf, very bushy, and very leafy, and has very fine threadlike roots. ”

“ Spirocyrtidium, Haeckel.
Definition.—Shell conical, gradually dilating towards the wide open terminal mouth.
1. Spirocyrtis scalaris, n. sp. (Pl. 76, fig. 14) .
Shell conical, gradually dilating towards the wide open mouth, with ten to twelve spiral convolutions, which correspond to the same number of short and broad chambers or joints, gradually increasing in breadth; all joints form together a spirally winding staircase. The length or height of the single joints or stairs is about equal, and each bears four or five transverse rows of small, square pores. ”

“ Sinistral, or Left-handed Shells.—The vast majority of univalve spiral shells are normally dextral, i.e. when held spire uppermost, with the aperture towards the observer, the aperture is to the right of the axis of the spire. If we imagine such a shell to be a spiral staircase, as we ascended it we should always have the axis of the spire to our left. ”

“ Bl. The shells are described as chambered, symmetrical, convolute in part of their extent, but constantly straight towards the termination. The genus Spirula, which is admitted into this family, does not properly belong to it, any more than to the Lituolæ of Lamarck, in which it is also placed. It does not agree with the descriptions of either. This family partly corresponds with the "Lituolées," Lam. and contains the genera Lituola, Ichthyosarcolites, Spirula, Hamites and Ammonoceras.
LITUACEA. Lam. A family of the order Polythalamous Cephalopoda, Lam. containing the genus Spirula, fig. 471. ”

“ Nautilacea. Two genera. 1. Genus Spirula. Pl. XII. Animal. Body elongated, cylindrical, terminated posteriorly by two lateral lobes partially concealing the shell; head provided 155with five pairs of tentacula, of which two are longer than the others.
Shell. Very symmetrical, longitudinally twisted throughout nearly all its extent; the cone spiral, conical, regular, circular; whorls of the spire very evident; partitions simple, concave, and pierced by a single syphon. Inhabits the West Indian seas. One species.
Spirula Peronii. (Nautilus spirula. Lin.) 2. Genus Nautilus. Pl. XII. Animal. ”

“ They form large, dark green, felted masses, and are sometimes known as “green felts.” Some species grow also on the wet ground about springs. An examination of one of the masses shows it to be made up of closely matted, hair-like threads, each of which is an individual plant.
In transferring the plants to the slide for microscopic examination, they must be handled very carefully, as they are very easily injured. Each thread is a long tube, branching sometimes, but not divided into cells as in Spirogyra or Cladophora. ”

“ The frontal aperture is typical, as is also the general form of the shell. The spiralia are conical, and the tips probably acute. In No. 6 the position of the spiralia, their form and that of the aperture are normal. Nos. 6 and 9 show spines on the spires. The spines are closely set, thick, blunt, and nearly twice as long as broad. In fact, some appear to be nearly as large at the tips as at the base. In No. 9 the spires are normal, except that, instead of being flaring conical, they are more in the shape of a folded shield shape with acute apex. ”

“ In some instances the flattened spire consists of but one whorl, it is then unispiral; and when scarcely one turn is completed, it is described as subspiral. When the layers are applied upon each other in such a manner that the nucleus is central, and the edges of the subsequent layers are extended beyond each other all around, so as to form rims, the operculum is described as concentric; if the nucleus is lateral, or at one side without being spiral, it is lammellated ”

“ They seem to have begun life together, or rather, perhaps, the spirifer is somewhat the older brother. They voyaged through the same seas, and anchored themselves to the same ocean-bed, sometimes among mud and ooze, and often among bowers of corals and stone-lilies. They visited together the most distant parts of the world, from China to Chili, and from Hudson's Bay to New Zealand. I have sometimes laid open fragments of limestone where they lay thickly clustered as though they had ended a life of friendship by dying very lovingly together. ”

“ The new findings show the Spiro site as one of the premier trading and religious centers of prehistoric America. Situated in a narrow valley of the Arkansas River, the Spiroans were in a strategic position to control traffic, trade and communications along this waterway, especially between the small villages scattered among the Ouachita Mountains to the south and the Ozarks to the north. Both of these regions were rich in raw materials favored by the Spiro people. ”

“ Fibres are coiled spirally in the minute vessels of flowering plants, and are not wholly wanting even among fungi. The leaf-organs are very generally spirally arranged; the leaf-stalks are often so twisted as to bring leaves on one plane which otherwise would occupy several. In the leaf itself we have a spiral twist taking place constantly in Alstrœmeria, in Avena, and other plants. A similar tendency is manifested in the flower-stalks, as in Cyclamen and Vallisneria, and the whole inflorescence, as in Spiranthes. Even the bark and wood of trees is often disposed spirally. ”

“ It is an object of considerable interest even among curious marine animalcules; one or two species inhabit fresh water. The spiral-mouthed Spirostomum are among the largest of the class, and in sunlight are visible to the naked eye as slender golden threads of about 1⁄10th of an inch in length. The mouth slit, extending half the length of the body, is bordered on one side by cilia. The body is cylindrical and the surface covered with rows of cilia. Its multiplication takes place by transverse fission through the middle. ”

“ As a problem in engineering, it is clear that the shape of the body is not responsible for the spiral course, for almost every conceivable shape is met with in organisms swimming in spiral paths. The frequent spiral turns in the path of stylonychia cannot be the result of the shape of the body, which is almost, if not quite, as well adapted for swimming through the water as is that of a euglena or a fish, but for revolution on its long axis it is not nearly so well adapted. ”

“ Orthoceratites, Baculites, Hamites, Scaphites, Belemnites, &c. (See Pl. 44,) in which the last, or external chamber, seems to have been too small to contain the entire body of the animals that formed them, by Peron's discovery of the well-known chambered shell, the Spirula, partially enclosed within the posterior extremity of the body of a Sepia (Pl. 44; Figs. 1, 2.) ”

“ It is of course quite possible theoretically, that some of the unsymmetrical structures on an organism that habitually swims in spirals, are the result of its spiral swimming, and that other structures which go to make the organism unsymmetrical, are the cause of the spiral swimming. This hypothesis is not an attractive one, however, for, because of the endless variety of asymmetrical differentiation in spiral swimming organisms, it would be impossible to tell for the large majority of organs or organelles whether they were the cause or the effect of spiral swimming. ”

“ Conical, convolute, with a short spire, consisting of numerous whorls; and narrow lengthened aperture, terminating in a slight emargination at each extremity; outer lip thin; epidermis thin; operculum small, pointed, horny.—Obs. This well-known genus of shells is easily distinguished from any other, by its conical form, its smooth columella, its narrow aperture, and thin outer lip. The form of the spire varies from flat and even partially concave, to a regular pyramidal cone; and the upper edges of the whorls are rounded in some species, angulated in others, and in some are waved or coronated. ”

“ Neither does the insect receive the air through mouth or nostrils as we do. Along the sides of the body are certain oval apertures called “spiracles,” from the Latin word spiro, which signifies breathing. These spiracles can easily be seen by examining an ordinary silkworm. They are situated in the soft and flexible skin which connects the rings or segments of which all insects are composed, and pass directly into two large air-tubes which run on either side of the body. ”

“ The spiral form of structure is one in which Nature seems to delight. We find it in the organic world allied with objects of the greatest interest and beauty. 257The ammonite, a magnificent spiral shell sometimes exceeding three feet in diameter, belongs to a type which dominated the waters of the globe in secondary times, and which still survives in the nautilus. ”

“ No doubt, just as in the case of our molluscan shells, we have a tendency to variation, both individual and specific, in the constant angle of the spiral; some elephants, and some species of elephant, undoubtedly have a higher spiral angle than others. But in most cases, the angle would seem to be such that a spiral configuration would become very manifest indeed if only the tusk pursued its steady growth, unchanged otherwise in form, till it attained the dimensions which we meet with in the mammoth. ”