- 1804. Attraction-Spheres and Centrosomes, 457 
cell—the attraction-sphere with a centrosome—which is of 
universal distribution in both plants and animals—at least in all 
cells which divide by karyokinesis. This body propagates 
itself by division. Asa rule, there seem to be two of these 
bodies for each resting nucleus, but in some cases only one. 
They remain constantly ouside of the nucleus. They appear 
to be the organs which direct nuclear division. It seems that 
there is a union of the attraction-spheres and centrosomes ac- 
companying the male nucleus with those of the female nucleus 
uring impregnation of the ovum. The bodies migrate and 
divide, and are thus carried from one cell to the other 
throughout the entire organism, whether plant or animal. 
Ann Arbor, Mich., F¥une, 1894. 
REFERENCES. 
The following is a list of prt more important references on the subject of cen- 
and attraction-spher 
1. Boveri, Zellenstudien. fens ‘acti Zeits. Naturwiss. 22:— 
2. Bir ice t, O., Was sind die se und ihre peprctiannie? Anat. 
eig. 7; 222-231. 
3. Birger O., Ueber Ataktionssphiaren in Zellkérpern einer Leibesfliissig- 
keit. ‘Anat Anze 6: 484-9. ie 
4. Biitschli, Ueber die sorceauenel Central g 
. Naturhist.-Med. Viveigs ae sire eerann N. F. t. — =, 
Ds | A 
[Heft 5.) 
+ F lemming W. Pg che gpa ge und ong el tt in Gewebezellen und . 
poet ellen. Anat. Anzeig. 6: 78-81. 
Anat, 37: 685 — ~751. Vv 
7. Flemmi ming, W., Ueber Zalibarlane. Verhandl. d. Anat. Gesells. V Ver- 
sammlung zu Miinchen. —: 12 
8, te W., Ueber Theilung bere Revkieceudl bei pats bens und pate 
m Attraktionss haren. Archiv f. Mikr. Anat. rence 0: 
9. Fick, § R, Be Bemerk gerd zu O. Biirger’s Erklarungsversuch der aniceae 
Sphdren. Anat. Anzeig. 7: 464%7. 18 
an ,..; Sarl etecnes 4 des ‘sphére es attractives’ dans ee vai gin vég- 
ue tales. Comptes Rendus Hebd. Acad. Sci. 112: 539-42. cae 
““Uignard, L., Nouvelles Etudes sur la fécondation. Copier 
é j z les plantes et chez les ani- 
n 
m 96. 1891. _ 
@. Hansemann, D , Ueber args ey -Aticaktionpenhizes in ruhenden 
sspharen der 
Zellen, Anat A 1-7. 189 
15. Heidenhai a. ae Anzeg, 6:4 nT Protoplas asma. Festschri 
gen Doctorjubilaum von v. Killiker. Leipzig, 1892, pp- ! 
oe 66 . 1893.) ee fine 
. Sidenhain, M., Neue Untersuchungen fiber die Centralkérpe kr. Anat. 
43: 42 ae zum eth und Zellenprotoplasma. Archiv. £. Mikr. 
8. 1894. 
- zum 50-jahri- 
11-166.—(Bot 
