SPECIAL SUBJECTS. 
Gen. Sub . 25 
Hoffmann, 0. K. Ueber den Ursprung und die Bedeutung der sogen- 
annten “ freieu ” Kerne in dem Nahrungsdotter bei den Knochen- 
ftschen. Z. wiss. Zool. xlvi, 4, pp. 517-548, 1 pi. 
Ischikawa, C. Ueber die Herkunft der weiblichen Geschlechtszellen 
bei Podocoryne carnea , Sars. Z. wiss. Zool. xlvii, 4, pp. 621-625, 
6 figs. 
— —. [See Weismann, A.] 
Kastschenko, N. Zur Frago fiber die Herkunft der Dotterkerne im 
Selachierei. Anat. Anz. iii, pp. 253-257, 1 pi. 
Several nuclei in unsegraented egg. 
Korotneff, A. de. Contribution a l’dtudes des Hydraires. Arch. Z. 
exp6r. vi, pp. 21-31, 2 pis. 
The ovum of Myriothela arises from a primordial cell of ectodermic 
origin, which gives origin to over twenty secondary germinal elements. 
One of these forms the germinal vesicle, the others disappear, but form 
tho formative plasma, while the nuclei of vitelline colls afford a third 
nutritive contribution to the common mass of the ovum. The malo 
elements arise like the ova. 
Korschelt, E. Zur Bildung der Eihfilleu, der Mikropylen, und Chorion- 
anhangen in den Insekten. N. Acta Ac. L.-C. Nat. cur. li, pp. 183- 
252, 5 pis. 
The formation of the chorion in insect ova is entirely similar to the 
formation of the cuticle in the adult skin. (Expression of adult diathesis 
in ovo.) 
Kultsciiitzky, N. Die Befruchtungsvorgange bei Ascaris megalo- 
cephala. Arch. mikr. Anat. xxxi, 4, pp. 567-593, 2 pis. 
. Ueber die Eireifung und die Befruchtungsvorgange bei Ascaris 
marginata. Op. cit. xxxii, pp. 671-682, 2 pis. 
Of. Review by O. Zaciiarias, Biol. Ceutralbl. viii, 12, p. 367. 
. Ergebnisse einer Untersuchung fiber die Befruchtungsvorgange 
bei Ascaris megalocephala. SB. Preuss. Akad. 1888, ii, iii, pp. 17-21. 
(1) As to formation of polar bodies, agrees in the main with Boveri, 
but two achromatic spindle figures are seen lying beside one another. 
(2) Modifications of the spermatozoon. It does not seem as if the whole 
chromatin went to the formation of the male pronucleus. (3) The for- 
mation of two similar pronuclei, with originally very different com- 
ponents, shows that the process is something sui generis. (4) Three 
pronuolei may occur, perhaps due to the entranco of a binucleate sper- 
matozoon. (5) The karyokincsis of each pronucleus is independent ; 
fusion was not observed. (6) The essence of fertilisation consists in the 
process by which the sperm-nucleus— an element foreign to the ovum — 
is modified into an essentially inseparable element, a nucleus of the 
same. 
Lameere, A. Sur des oeufs anormaux de V Ascaris megalocephala. Bull. 
Ac. Belg. xv, 6, pp. 980-984, 1 pi. 
