Carmen watched with excitement as the foal's feet could be seen inside a thin sac... first one and then the other.
The spores, as in the heterosporous Pteridophyta, are of two kindsmicrospores (pollen grains) borne in microsporangia (pollen sacs) on special leaves (sporophylls) known as stamens, and macrospores (embryo-sac) borne in macrosporangia (ovules) on sporophylls known as carpels.
It does not at first appear to be the same with the bulkier plants, such as the ordinary green herbs, shrubs or trees, but a study of their earlier development indicates that they do not at the outset differ in any way from the simple undifferentiated forms. Each commences its existence as a simple naked protoplast, in the embroyo-sac or the archegonium, as the case may be.
Xxi.; On the Prophases of the Heterotype Mitosis in the Embryo-sac Mother-cell of Lilium, Ann.
Strasser, " Luft sac ke der Vogel," Morph.
The old town is composed of winding streets and culs-de-sac bordered by old houses in the Flemish style.
Levites, Prophet, Sac Rifice).
In the majority of the Megascolicidae each sac is provided with one or more diverticula, tubular or oval in form, of a slightly different histological character in the lining epithelium, and in them is invariably lodged the sperm.
In Hyperiodrilus the whole spermatheca is thus included in a corresponding sac, which is of great extent.
This sac has been already referred to as a coelomoduct.
Sperm, spermatheca; sp. o, its external orifice; sp. sac, spermathecal sac; ov, sac containing ovary;.
R.o, egg sac; od, oviduct.
Sp', Spermathecal sac involving the last.
Thus, in Philaemon pungens (Lambert) it has the form of a large sac, into which open by a single orifice the conjoined oviducts.
In this Annelid later the sac in question joins its fellow, passing beneath the nerve cord exactly as in the leech, and also grows out to reach the exterior.
The sole difference is therefore that in Eudrilus the ovarian sac gives rise to a tube which bifurcates, one branch meeting a corresponding branch of the other ovary of the pair, while the second branch reaches the exterior.
In the former, the duct, leading from the ovarian sac, and swelling along its course into the spherical sac, the "spermatheca," is highly suggestive of the oviduct and receptaculum of the Eudrilidae.
The Gastropoda are mainly characterized by a loss of symmetry, produced by torsion of the visceral sac. This torsion may be resolved into two successive movements.
Movement flexure is also produced by the coiling of the visceral sac and shell; primitively the latter was bowl-shaped; but the ventral flexure, which brings together the two extremities of the digestive tube, gives the visceral sac the outline of a more or less acute cone.
Each renal organ is a sac lined with glandular epithelium (ciliated cell, with concretions) communicating with the exterior by its papilla, and by ce, Cerebral ganglia.
Subsequent connected by nerve investigations carried on under the directo the streptoneur tion of the same naturalist have shown ous visceral loop. that the larger as well as the smaller renal sac is in communication with the pericardium.
Below the surface these walls are excavated with blood-vessels, so that the sac is practically a series of blood-vessels covered with renal epithelium, and forming 6 Cephalic tentacle.
The larger renal sac (remarkably enough, that which is aborted in other FIG.
12, and forms a large sac on half of the upper surface of the muscular mass of the foot.
Here it lies close upon the genital body (ovary or testis), and in such intimate relationship with it that, when ripe, the gonad bursts into the renal sac, and its products are carried to the exterior by the papilla on the right side of the anus is FIG.
It is surrounded by a ridge of cells which gradually extends over the visceral sac and secretes the shell.