The old district of Assiniboia, the result of the efforts in colonization by the earl of Selkirk in 1811 and succeeding years, was the nucleus of the province.
In the middle ectoderm cell are seen a nucleus and three nematocysts, with trigger hairs projecting beyond the cuticle.
Another Roman basilica forms the nucleus of the cathedral.
Holtzmann (1872) subjected both Colossians and Ephesians to a rigorous examination, and found in Colossians at least a nucleus of Pauline material.
Von Soden (1885), with well-considered principles of criticism, made a similar examination and found a much larger nucleus, and later still, (1893), in his commentary, reduced the non-Pauline material to a negligible minimum.
I, 0.) is also an elongated cell, with a thin lining of protoplasm, but destitute of a nucleus, and always in communication with the next cell of the leptom strand by perforations (in Pteridophytes often not easily demonstrable), through which originally pass strings of protoplasm which are bored out by a ferment and converted into relatively coarse slime strings, along which pass, we must suppose, the organic substances which it is the special function of the leptoids to conduct from one part of the plant to another.
The nucleus was definitely recognized in the plant cell by Robert Brown in 1831, but its presence had been previously indicated by various observers and it had been seen by Fontana in some animal cells as early as 1781.
In Spirogyra the pyrenoids are distinctly connected by cytoplasmic strands to the central mass of cytoplasm, which surrounds the nucleus, and according to some observers, they increase exclusively by division, followed by a splitting of the cytoplasmic strands.
Starch exists, in the majority of cases, in the form of grains, which are composed of stratified layers arranged around a nucleus or hilum.
The nucleus is regarded as a controlling centre of cell-activity, upon which the growth and development of the cell in large measure depends, and as the agent by which the transmission of specific qualities from one generation to another is brought about.
The Structure of the Nucleus.In the living condition the resting nucleus appears to consist of a homogeneous ground substance containing a large number of small chromatin granules and one or more large spherical granulesnucleolithe whole being surrounded by a limiting membrane which separates it from the cytoplasm.
The staining reactions of the various parts of the nucleus depend to some extent upon their chemical constitution.
They are more easily seen, when the nucleus is about to undergo mitosis, at the ends of the spindle, where they form the centres towards which the radiating fibres in.
In multinucleate cells the division of the nucleus is independent of the division of the cell.
Mitosis.In indirect nuclear division the nucleus undergoes a series of complicated changes, which result in an equal division.
The spindle arises partly from the cytoplasm, partly from the nucleus, or it may be derived entirely from the nucleusintranuclear spindleas occurs in many of the lower plants (Fungi, &c.).
A layer of delicate filamentous cytoplasmkinoplasmmay collect around the nucleus, or at its poles, out of which the spindle is formed.
The wall of the nucleus breaks down, and the cytoplasmic spindle-fibres become mixed with those derived from the nuclear network.
Cell Division.With the exception of a few plants among the Thallophytes, which consist of a single multinucleate cell, Caulerpa, Vaucheria, &c., the division of the nucleus is followed by the division of the cell either at once, in uninucleate cells, or after a certain number of nuclear divisions, in multinucleate cells.
Reduction in size is due to A, Two vermiform nuclei in the emthe absence of cytoplasm, bryo sac; one approaching the eggwhich is in some cases so nucleus, the other uniting with the 11 ~ ~h ~h upper polar nucleus.
Sma in amoun a B, Union of the vermiform nuclei cell consists mainly of a with the egg-nucleus and the two nucleus.
In many of the Fungi the non-motile male cell or nucleus is carried by means of a fertilizing tube actually into the interior of the egg-cell, and is extruded through the apex in close proximity to the egg nucleus.
Even in the multinucleate oosphere of Albugo bliti the nuclei fuse in pairs; and in the oospheres of Sp/zaero plea, which may contain more than one nucleus, the egg nucleus is formed by the fusion of one only of these with the spermatozoid nucleus (Klebahn).
In many Gymnosperms the male nucleus penetrates the female nucleus before fusing with it (Blackman, Ikeno).
During the process of fertilization in the Angiosperms it has been shown by the researches of Nawaschin and Guignard that in Lilium and Fritillaria both generative nuclei enter the embryo sac, one fusing with the oosphere nucleus, the other with the polar nuclei (fig.
He discovered the nucleus of the cell.