They may be scattered spicules of lime, separated plates joined by connecting rods, or overlapping plates; or they may be fitted together so as to form a continuous shell.
The spicules of lime secreted in the polyp unite or fuse into a tube or cylindrical skeleton.
The substance of the coral is semi-cartilaginous, with scattered spicules of lime which give it stability.
In some species it is covered by a great number of calcareous spicules or granules which are embedded in the leathery mantle tissue.
In this species the spicules of lime in the skin are shaped like wheels instead of anchors.
This mass consists of polyps closely united, and has throughout its substance spicules of carbonate of lime, making it a kind of calcareous crust or bark.
The walls of the body are tough and muscular, with small calcareous deposits or spicules of various shapes in the skin.
In other species the spongin is intermixed with spicules of silica, or of carbonate of lime, in various shapes.
Spicules of lime are present in the substance of the branches, which gives them stability.
Body elongated; visceral mass marked off from foot posteriorly; dorsal appendages absent, or reduced to a single pair; spiculesin the integument.
Often few quadriradiate or few thorny triradiate spiculesare interspersed among the others.
Numerous fine siliceous spiculeslie scattered irregularly in a finely granular or porous matrix.
I formerly regarded these peculiar calcareous corpuscles, whose solubility in mineral acids I had observed, as spicules of a Thalassicollid, and hence described the species in my Monograph as Thalassosphaera morum (L.
Brandt concluded, from the varying size of the median bars in the twin-spicules of Sphaerozoum, that these siliceous structures grow by intussusception (L.
Identify the endoderm and ectoderm cells, the spicules or fibers, and, among the spicules or fibers, irregular amoeboid cells, sometimes called mesoderm cells.
Notice the arrangement, shape, and length of the spicules and of the fibers.
With a ring-knife any irregular spiculesor projections can be smoothed down.
Any projecting corners or loose spicules of bone are removed.
All danger from pursuit was past, and they jogged the teams slowly northward, while all about them fell the frost spicules in a feathery shimmer of tinsel.
Echinoderms agree also in having a calcareous outer skeleton or body-wall usually in the condition of definitely-shaped plates or spicules fitted either movably or rigidly together.
Examine under a microscope and note the abundance of spicules and the variety in their form.
The others have a skeleton or hard parts composed of interwoven fibres of the tough, horny substance called spongin, or of hosts of fine needles or spicules of silica or of carbonate of lime.
All other sponges are grouped as Non-Calcarea, the members of this group either having no skeleton at all, or having a skeleton composed of siliceous spicules or of spongin fibres.
These spicules are composed of carbonate of lime and can be dissolved by pouring on to them a drop of hydrochloric acid.
The lime and siliceous sponge spicules exhibit a great variety of outline, some being anchor-shaped, some cross-shaped, and some resembling tiny spears or javelins.
The skeleton of a sponge whether composed of interlacing fibres or of short spicules is always invisible from the outside when the sponge is alive.
Sea urchins were also abundant, and sponges contributed their spicules to form nodules of flint.
The cuticle, in some species very thick, contains numerous spicules which are long, hollow and calcified; they are secreted by epithelial papillae.
The long, dark cells are brown cystidia, termed spicules by some to distinguish them from the colorless cystidia.
The color is the same as that of the pileus or dark bay brown, and shining, and seems to be due to large numbers of spicules similar to those on the gills.
The color is light leather color, brick red or bay, the color and color variations being due to numbers of colored cystidia or spicules scattered over the surface of the gills and on the edge.
Young has, however, recently found true spicules of Spongilla in the Purbeck beds.
The silicious sponges with simple spicules appear to have existed as far back as the Siluro-Cambrian, and there is believed to be almost as early evidence of horny or corneous sponges.
The periosteum is thick and vascular, and when detached carries with it plates and spicules of soft porous bone.
Not long after the closure of the blastopore, calcareous spicules make their appearance in the larva as delicate unbranched rods pointed at both extremities.
Metschnikoff was the first to give this account of the development of the spicules in Sycandra, but Prof.
In silicious sponges the spicules are composed of silica, and are generally deposited around axial rods in concentric layers.
Silicious spicules next appear in its structure, and it then attaches itself to a rock and assumes its mature form.
Ledenfeld again illustrated this stage of his lecture by means of a number of microscopic slides in which the variety of shape and size of these spicules and "spongin" fibers were shown.
The skeleton of calcareous sponges consists of a number of spicules composed of carbonate of lime.
These spicules are of very varied though regular shape, but ordinarily assume a rod-like needle shape or else a stellate form.
Little spicules licked out from their flexing stalks and jabbed, unsensed, into Cully's body to draw nourishment.
Their spicules withdrew and jabbed, withdrew and jabbed.
In our section of a sponge we may follow the winding channels which connect one part of the sponge with the other, and we see that the body is a mass of fibers made up of curious and beautifully shaped objects called spicules (Fig.
The sponge of commerce is the skeleton, the mass of living spicules after all the animal matter has been removed and the framework, elastic and soft, thoroughly bleached.
The spiculesare the bones of sponges, the hard portion, the framework.
The medullary portion is densely crowded with spicules of different shape from those in the cortex, and in some forms the spicules are cemented together to form a hard supporting axis.
With very few exceptions a calcareous skeleton is present in all Alcyonaria; it usually consists of spicules of carbonate of lime, each spicule being formed within an ectodermic cell (fig.
In the Tubipondae the spicules of the proximal part of the body-wall are fused together to form a firm tube, the corallite, into which the distal part of the zooid can be retracted.
The calcareous skeleton of the Pennatulacea consists of scattered spicules, but in one species, Protocaulon molle, spicules are absent.
Spicules vary exceedingly in size and shape, and some of those found in siliceous sponges are very complex in structure and elegant in form.
One of the microsporic siliceous spiculeswhich occur abundantly in the texture of sponges, and are sometimes found fossil, as in flints.
A division of Spongi\'91 in which the spicules are siliceous and have four branches diverging at right angles.
Having four branches diverging at right angles; -- said of certain spicules of sponges.
After the formation of the structureless layer between the ectoderm and entoderm, calcareous spicules make their appearance in it as delicate unbranched rods pointed at both extremities.
The extremity of the cylinder opposite the attached surface is flattened, and though surrounded by a ring of four-rayed spicules is itself free from them.
The fact that birotulate spicules are often found in close association with them, is particularly noteworthy.
Spicules arranged irregularly in this layer, as a rule being more nearly vertical than horizontal but pointing in all directions, not confined externally by a membrane; no external layer of horizontal spicules.
The measurements of the spicules and gemmules of an Indian specimen and of one from Lehigh Gap, Pennsylvania, are given for comparison:-- Travancore.
Skeleton-spicules smooth, stout, amphioxous, as a rule straight or nearly straight, not infrequently inflated in the middle or otherwise irregular.
Martens) from Borneo, from which it may be distinguished by its smooth skeleton-spicules and the deeply indented disk of its gemmule-spicules.
The spicules variable in quantity, arranged irregularly among the spaces of the cellular coat and usually forming a sparse horizontal layer on its external surface.
Pilulina has a neat globular shell of sponge-spicules and fine sand.
It is noteworthy that though of similar habitat each species selects its own size or sort of sand, some utilizing the siliceous spicules of sponges.
Defn: An order of sponges, having simple siliceous spiculesand keratose fibers; -- called also Keratosilicoidea.
Defn: A division of Spongiæ in which the spicules are siliceous and have four branches diverging at right angles.
Defn: Having four branches diverging at right angles; -- said of certain spicules of sponges.
Defn: One of the microsporic siliceous spicules which occur abundantly in the texture of sponges, and are sometimes found fossil, as in flints.
Note: Spicules vary exceedingly in size and shape, and some of those found in siliceous sponges are very complex in structure and elegant in form.
With these are numerous spicules of sponges and silicious cell-walls of the minute one-celled plants called Diatoms.
They are hollow within, with radiating pores and plates, calcareous in some, and in others with siliceous spiculeslike those of modern sponges.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "spicules" in a variety of sentences. We hope that you will now be able to make sentences using this word.
