Archive image from page 28 of The development of the human. The development of the human body : a manual of human embryology . developmentofhum00mcmu Year: 1914 SPERMATOGENESIS 17 ten plus two, i. e., twelve univalent chromosomes, while those of the other class will have received the equivalent of only ten. The transformation of the spermatids into spermatozoa takes place while they are in intimate association with the Sertoli cells, a number of them fusing with the cytoplasm of an enlarged Sertoli cell, as shown in Fig. 6, s, and probably receiving nutrition from it. In each spermatid there
Archive image from page 28 of The development of the human. The development of the human body : a manual of human embryology . developmentofhum00mcmu Year: 1914 SPERMATOGENESIS 17 ten plus two, i. e., twelve univalent chromosomes, while those of the other class will have received the equivalent of only ten. The transformation of the spermatids into spermatozoa takes place while they are in intimate association with the Sertoli cells, a number of them fusing with the cytoplasm of an enlarged Sertoli cell, as shown in Fig. 6, s, and probably receiving nutrition from it. In each spermatid there is present in addition to the nucleus, an Fig. 8.—Diagram Illustrating the Behavior of the Chromosomes in Human Spermatogenesis. The upper figure shows the mitotic spindle of a primary spermatocyte with the two accessory chromosomes passing to one pole. The two figures in the second row repre- sent the chromosomes of such a spindle in an anaphase; seen from either pole, and the figures of the last row represent spermatids derived from the two classes of secondary spermatocytes.—(Based on Guyer.) archoplasm sphere and two that have migrated from the archoplasm and lie free in the cytoplasm. The centrosomes and the archoplasm sphere take up their position at opposite poles of the nucleus, the archoplasm eventually forming the head-cap of the spermatozoon, and from one of the centrosomes a slender axial Doubt has been thrown upon the accuracy of these observations by Gutherz, who, while he finds a structure in the human spermatocyte which he identifies as an accessor)' chromosome, claims that it divides similarly to the other chromosomes. He does not find, therefore, any numerical difference in the chromosomes of the spermatids dividing them into two classes, although there may be qualitative differences indistinguishable by our present technique.
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