SPECIAL SUBJECTS. 
Gen. Sub . 23 
[Boveri, Tii.] The same separately. Jena: 8vo. 
The several chromosomes may be traced throughout maturation. The 
chromosomes present in the division of the egg-cell are identical with 
those which the cell had at its formation. The elements emitted in the 
polar globules seem identical with those that remain in the egg. The 
nucleus is not a unity so much as a common house for a number of 
equivalent, mutually independent chromosomes. For every species the 
number of chromosomes is constant. The polar globules are rudimentary 
ova. When the second polar spindle is not removed, the number of 
chromosomes in such a (parthenogonetic) egg is the same as in a ferti- 
lized ovum. 
Chatin, J. Sur les Cellules initiales de l’Ovaire chez les Hydres d’eau 
douce. C.R. cx, pp. 414-416. 
What have been described as free nuclei are really minute cells. 
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pp., 9 pis. & figs. 
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xl, pp. 4 & 5. 
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* . Sur la Formation et la Diff^renciation des Elements Sexuels qui 
interviennent dans la Fecondation. J. Microgr. xiv, No. 6. 
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xiii, pp. 551-558, 1 pi. 
Henking, H. Ueber Befruchtungsvorgange im Insektenei. Yerh. 62 
Yers. deut. Nat. p. 264 ; Biol. Centralbl. x, pp. 439 & 440. 
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Eiern der Insekten. I. Das Ei von Pieris brassicce, L., nebst 
Bemerkungen fiber Samen und Samenbildung. Z. wiss. Zool. xlix, 
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Henneguy, L. F. Nouvelles recherches sur la Division des Cellules 
embryonnaires chez les Vertebras. C.R. cxi, pp. 116 & 117. 
Attractive spheres and central corpuscles in the ova of the Trout. 
