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2. They migrate within the entoderm to a point immediately be- 
neath the notochord, from which a large proportion of them continue 
upward in the mesentery. The great majority of these reach the 
sex-gland anlagen in the peritoneum on each side of the root of the 
mesentery. 
3. In both ovary and testis, a portion of the sex-cells are carried 
into the sex-cords, where they give rise to spermatogonia in the 
testis, and probably degenerate in the ovary. In the testis, a majority 
of the sex-cells come to lie in the sex-cords, while in the ovary, the 
greater part of them remain in the germinal epithelium, there to be- 
come oögonia. Those that remain in the peritoneum of the testis, 
degenerate. 
4, The sex-cells lie among the peritoneal cells, but are not derived 
from them. 
5. No essential differences in origin or character were to be ob- 
served between oögonia and spermatogonia. 
(Eingegangen am 14. April 1906.) 
Literature. 
Auten, B. M., The Embryonic Development of the Ovary and Testis of 
the Mammals. Amer. Journ. of Anat., Vol. 3, 1904. 
-—, The Embryonic Development of the Rete-Cords and Sex-Cords of 
Chrysemys. Ibid., Vol. 5, 1905. 
Bauerani, G., Lecons sur la generation des Vertébrés. Paris 1879. 
Barrour, F. M., On the Development of the Elasmobranch Fishes, Urino- 
genital System. A Monograph upon the Development of the Elasmo- 
branch Fishes. London 1878. 
Bearp, J., The Morphological Continuity of the Germ-cells in Raja batis. 
Anat. Anz., Bd. 18, 1900. 
—, The Germ-cells of Pristiurus. Ibid., Bd. 21, 1903. 
—, The Numerical Law of Germ-cells. Ibid. Bd. 21, 1903. 
—, The Germ-cells. Journ. of Anat. and Physiol., 1904. 
Benpa, C., Zur Spermatogenese und Hodenstruktur der Wirbelthiere. 
Anat. Anz., Bd. 2, 1887. 
—, Untersuchungen über den Bau des funktionierenden Samenkanälchens 
einiger Säugethiere und Folgerungen für die Spermatogenese dieser 
Wirbelthierklasse. Arch. f. mikr. Anat., Bd. 30, 1887. 
—, Entwickelung des Säugethierhodens. Verhandl. d. Anat. Ges. 1889. 
—, Ueber die Spermatogenese der Vertebraten und höheren Everte- 
braten. 2 parts. Arch. f. Anat. u. Physiol., Physiol. Abt., 1898. 
Bou, U., Beiträge zur Entwickelungsgeschichte der Leibeshöhle und der 
Genitalanlage bei den Salmoniden. Morph. Jahrb., Bd. 32, 1904. 
Bouin, P., De quelques phenomenes de dégénérescence cellulaire dans 
le testicule jeune des mammiféres. Bibl. Anat., T. 3, 1895. 
