| 单词 | spermatozoid |
| 例句 | The male reproductive apparatus in the lower, consisting of a cell or other cavity in which spermatozoids are produced; Ð called also spermary. Webster's Unabridged Dictionary 2012-03-24T02:00:23.513Z Similar spermatozoids were observed in some species of Zamia by H. J. Webber, and more recent work enables us to assume that all cycads produce ciliated male gametes. Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 7 "Gyantse" to "Hallel" 2011-12-26T03:00:11.613Z The Crustacea are—with the exception of the Cirrhipedia—remarkable for having stiff, motionless spermatozoids. Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 3 "Apollodorus" to "Aral" Afterwards the contents of these latter cells become divided into numerous bacillary spermatozoids, which first break the wall of their mother cell, and then issue from the antheridium. Fungi: Their Nature and Uses At this moment it produces on the surface of the egg a coagulation, which prevents the entrance of a second spermatozoid. The Sexual Question A Scientific, psychological, hygienic and sociological study Prevost and Dumas, on the employment of several spermatozoids to fertilise one ovule, ii. The Variation of Animals and Plants Under Domestication, Volume II (of 2) The spermatozoids constitute the most striking link with both cycads and ferns. Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 7 "Gyantse" to "Hallel" 2011-12-26T03:00:11.613Z It is called an “antheridium,” and within are produced, by internal division, numerous excessively small spermatozoids. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses It is presumable that here, as in the Algæ, the spermatozoids introduce themselves into the cavity of the oogonium, and unite with the gonospheres. Fungi: Their Nature and Uses The letters e, f, and g, show a spermatozoid which has arrived too late. The Sexual Question A Scientific, psychological, hygienic and sociological study In the cases which have been most carefully investigated two spermatozoids have been found to arise from each of the small cubical cells of the central tissue. Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3 "Brescia" to "Bulgaria" The protoplasm of the other protuberance divides into many small masses, furnished with cilia, the spermatozoids or male cells. Scientific American Supplement, No. 531, March 6, 1886 To see the cilia it is necessary to kill the spermatozoids with iodine or some other reagent. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses Reproduction: by cell division, by the conversion of the cell contents into zoospores, and by resting spores, formed sometimes after conjugation; in other cases, probably, by fecundation by spermatozoids. Scientific American Supplement, No. 384, May 12, 1883 Then only commences activity of the nucleus of the egg, at the same time as fresh activity on the part of the nucleus of the spermatozoid. The Sexual Question A Scientific, psychological, hygienic and sociological study When mature the antheridium opens on being moistened and the spermatozoids become free in the water by the dissolution of the mucilaginous cell-walls enclosing them. Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3 "Brescia" to "Bulgaria" Each protuberance bursts, and some of the spermatozoids come in contact with and are absorbed by the oosphere, which then secretes a cell-wall, and after a time germinates. Scientific American Supplement, No. 531, March 6, 1886 K, mass of spermatozoids surrounded by the inner membrane of the antheridium. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses Fructification: zoospores produced from the cell contents of the filaments; resting spores formed from the contents of particular cells after impregnation by ciliated spermatozoids produced in distinct antheridial cells. Scientific American Supplement, No. 384, May 12, 1883 On some occasions a squad of spermatozoids advances to meet the descending egg, and numerous spermatozoids are often found in the tubes, even as far as the abdominal cavity. The Sexual Question A Scientific, psychological, hygienic and sociological study Fertilization is effected by the passage of a spermatozoid, attracted probably by means of a chemical stimulus, down the passage of the archegonial neck and its fusion with the ovum. Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3 "Brescia" to "Bulgaria" In Coleochæte, the male cell is a round spermatozoid, and the female cell an oosphere contained in the base of a cell which is elongated into an open and hair-like tube called the trichogyne. Scientific American Supplement, No. 531, March 6, 1886 Within is a mass of excessively small cells, each of which contains a spermatozoid. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses Reproduction by zoospores formed of the whole contents of a cell, with a crown of numerous cilia; resting spores formed in sporangial cells after fecundation by ciliated spermatozoids formed in antheridial cells. Scientific American Supplement, No. 384, May 12, 1883 This coagulation forms the vitelline membrane, which prevents the entry of other spermatozoids. The Sexual Question A Scientific, psychological, hygienic and sociological study Other adaptations concern the protection of the sexual organs and sporogonia, and the retention of water in the neighbourhood of the archegonia to enable the spermatozoid to reach the ovum. Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3 "Brescia" to "Bulgaria" From that moment, the two procreating elements are present in the mother at one and the same time: the female element, the ovule; and the male element, the spermatozoid. Bramble-Bees and Others The former divides repeatedly, until a mass of about thirty-two sperm cells is formed, each giving rise to a large spirally-coiled spermatozoid. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses The whole Order is relatively primitive, as shown most strikingly in its cryptogamic mode of fertilisation, by means of spermatozoids, which it shares with the maidenhair tree alone, among recent seed-plants. Darwin and Modern Science The nucleus of the spermatozoid, on the contrary, begins to grow rapidly. The Sexual Question A Scientific, psychological, hygienic and sociological study The individual antheridia are sunk in depressions from which the spermatozoids are in some cases forcibly ejected. Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3 "Brescia" to "Bulgaria" At the same time a nuclear liquid arising from the protoplasm of the egg becomes concentrated around the chromatin of the spermatozoid, while the nucleus of the egg remains in place and does not change. The Sexual Question A Scientific, psychological, hygienic and sociological study The spermatozoids are excessively small, and resemble those of the bryophytes. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses Each spermatozoid contains all the energies of the paternal and maternal ancestry of man, and each egg those of the paternal and maternal ancestry of woman. The Sexual Question A Scientific, psychological, hygienic and sociological study The egg and the spermatozoid both consist of protoplasm containing a nucleus. The Sexual Question A Scientific, psychological, hygienic and sociological study And even from the protoplasm of the egg without its nucleus, with the aid of a spermatozoid. The Sexual Question A Scientific, psychological, hygienic and sociological study J, a small portion of one of these more magnified, showing a spermatozoid in each cell. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses No spermatozoids are produced, the seed plants differing in this respect from all pteridophytes. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses They separate at the time of fertilization to allow the spermatozoids to enter the oögonium. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses But, while the spermatozoid has only a small nucleus and very little protoplasm, the egg has a large nucleus and a large quantity of protoplasm. The Sexual Question A Scientific, psychological, hygienic and sociological study If a ripe antheridium is crushed in a drop of water, after lying a few minutes the spermatozoids will escape through small openings in the side of the cells. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses After a few minutes this membrane is dissolved, and the spermatozoids are set free. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses In other cells, either of the same filament or else of the small male plants already mentioned, small motile cells, called spermatozoids, are formed. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses J, a single egg cell surrounded by spermatozoids. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses If, from pathological causes the entry of several spermatozoids takes place, there results, according to Fol, a double or triple monster. The Sexual Question A Scientific, psychological, hygienic and sociological study Occasionally one of these spermatozoids may be found attached to the trichogyne, and in this way fertilization is effected. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses The upper part consists of a single layer of large chlorophyll-bearing cells, enclosing a mass of very small, nearly cubical, colorless, sperm cells each of which contains an excessively small spermatozoid. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses By careful observation the student may possibly be able to follow the spermatozoid into the oögonium, where it enters the egg cell at the clear spot on its surface. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses The spermatozoids of a peat moss are shown in Figure 60, D. Like all of the bryophytes they have but two cilia. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses The spermatozoid swims by means of its tail to meet the egg. The Sexual Question A Scientific, psychological, hygienic and sociological study P, spermatozoids, killed with iodine, × 500. v, vesicle attached to the hinder end. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses After lying a few moments in the water, the wall of each sperm cell becomes completely dissolved, and the spermatozoids are released, and swim rapidly away with a twisting movement. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses When ripe, the antheridium opens at the end and discharges the spermatozoids, which are, however, so very small as scarcely to be visible except with the strongest lenses. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses |
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