SPECIAL SUBJECTS* G&U Sub. 23 
Boveri, Tn. Zeilen Studien. Heft n. Jen. Z. Nat. xxii, pp. 685-882, 
5 pis. 
Summary, J. R. Micr. Soc. 1880, ii, pp. 220-223. Review by 0. 
Zaciiarias, Biol. Centralbl. viii, 18, pp. 545-548. Review by 0. Zaciia- 
rias, of former Heft (see 1887), Biol. Centralbl. viii, pp. 17-19. 
There is no special “ bouchon d’impregnation,” nor micropyle. Poly- 
spermy is very rare, and only occurs when the ova are weak. Carnoy’s 
type of ovum (with two chromatin elements) is always fertilized by a 
spermatozoon with two chromatin elements, and there is a similar corre- 
spondence whon tho ovum contains only one chromatin olomout (in van 
Beneden’s type). The nuclei of ovum and spermatozoon are followed 
till they form the first segmentation spindle. The entire achromatin 
spindle-figure is due to the cell-substance. The cell-substance consists of a 
homogeneous matrix and a fine network, between the meshes of which lies, 
inter alia , a specific granular or filamentous substance — the archoplasma. 
The archoplasmic threads centred in protoplasmic centrosomata or central 
corpuscles behave like mu sole- fibrils. “ The movement of the nuclear 
elements is solely and wholly tho result of the contraction of the attached 
fibrils, and their final arrangement into an equatorial plate is the result 
of the equal action of the two archoplasmic spheres exerted through the 
said fibrils.” The equatorial plate stage is a condition of rest, par 
excellence , in the life of the cell. It is interrupted by the action of a 
new factor — the longitudinal splitting of the chromatin elements. The 
author seeks to justify his regarding this as “an independent expression 
of life, a reproductive act in the chromatin elements.” 
. Ueber den Anteil dos Spermatozoon an der Teilung des Eies. 
SB. Ges. Morph, iii, pp. 151-164. 
° . Ueber den Anteil des Spermatozoon an der Teilung des Eies. 
Miinchener med. Wochensohr. xxxv, 10, p. 172, also Nos. 14 & 15. 
0 . Ueber partielle Befruchtung. Op. cit. xxxv, pp. 570-572 & 613. 
Cunningham, J. T. Remarks on some Teleosteali Ova and their 
Development. Rep. Brit. Ass. Iviii, pp. 703 & 704. 
°Detmer, W. Ueber Richtungskorper. Humboldt, vii, 3, pp. 107 & 108. 
Dostoiewsky, A. Eine Bemerkung zur Furcbung der Eier der Ascaris 
megaloccphala. Anat. Anz. iii, pp. 646-648. 
Faussek, Y. Ueber die embryonale Entwicklung der Geschlechtsorgane 
bei den Afterspinne ( Phalangium ). Biol. Centralbl. viii, 12, pp. 359- 
363. 
The reproductive cells in .all probability originate directly from the 
yolk-cells, and afford another instance of early insulatiou from the 
general somatic cells. 
Fiedler, K. Ueber Ei- uud Samenbildung bei Spongilla Jluviatilis. Z. 
wiss. Zool. xlvii, 1, pp. 85-128, 2 pis. 
History of the ovum, and its follicle of appressed adjacent oells. The 
peripheral migration of the nucleus in maturation ; the spindle figures 
not yet observed. 
