Di ; 
493 
merely a mechanical importance, and taking no active part in the 
transmission of hereditary characters. 
The sperm centrosome has been found in the fertilized Echino- 
derm egg, particularly by O. and R. Herrwiea, Bovert and For. O. 
and R. Herrwic on account of its staining in a way similar to the 
Nebenkern, have been led to conclude that it was derived from this. 
But it is now generally agreed that the Nebenkern takes no part in 
the fertilization proper, but separates from the nucleus, and breaks 
down in the cytoplasm of the ovum very near the point of entrance 
of the spermatozoon. This view I can confirm from my observations. 
Picter has pointed out the erroneousness of this supposition that the 
centrosome is derived from the Nebenkern, and he inclines to For’s 
view that a part separates from the anterior end of the nucleus. But 
my work has led me to believe that the centrosome is present in the 
spermatozoon as a body separate and distinct from either the Neben- 
kern or nucleus; that it is derived directly from the original centro- 
some of the spermatogone, of which it is probably !/,, and in the 
fertilization process it penetrates the cytoplasm of the ovum with 
the nucleus of the spermatozoon. In the cytoplasm of the ovum it 
separates from its close apposition to the nucleus, and becomes the 
more plainly visible spermcentrosome with the characteristic ra- 
diations. 
Zoological Station, Naples, March 10, 1893. 
Nachdruck verboten. 
Halbbildung oder Ganzbildung von halber Gröfse ? 
Von Dietrich BarrurtH in Jurjew (Dorpat). 
In der lebhaften Discussion, die augenblicklich zwischen Roux, 
Driızsch und O. Herrwic über den morphologischen Wert der ersten 
Furchungskugeln geführt wird, spielt die wichtige Untersuchung CHA- 
BRy’s!) eine Hauptrolle. Auffallenderweise werden dabei die Resultate 
CHABrY’s von beiden Parteien als Stütze ihrer Anschauung heran- 
gezogen. DRIESCH ?) sieht das fundamentale Ergebnis dieser Versuche 
1) Contribution & l’embryologie normale et tératologique des Ascidies 
simples. Journal de l’anatomie et de la physiologie, 1887, p. 167 ff. 
2) Entwickelungsmechanische Studien. 1. Mitteilung. Zeitschrift für 
wissensch. Zool., Bd. 53, p. 160 ft. 
