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W. M. Wheeler 
is Seen to have outstripped the oocyte in volume, biit it is not long 
before the conditions are reversed, the oocyte gTOwing much more 
rapidly than the Nährzelle. Finally, when the egg-cell has attained 
the limit of its growth, the Nährzelle is foimd clinging to one point 
of its surface as a small deeply staining body. Aecording to Kor- 
SCHELT the Nährzelle nltimately disappears (»verschwindet«), but 
Braem, who is more explicit, says that it separates from the full 
grown egg and ))vielleicht wird der Rest der Nährzellen noch zum 
Theil von der Haemolymphe verdaut, zum anderen Theil, nämlich 
in so fern er für den Organismus nicht weiter verwendbar ist, wird 
er durch die Segmentalporen nach außen entfernt. In der Schleim- 
hülle, welche die frisch abgelegten Eier umgiebt, konnte ich die 
ausgeworfenen Näbrzellen mit Bestimmtheit nachweisen«. 
In another PolychajCte, Tomopteris^ each egg-cell when it leaves 
the ovary to pass into the body-cavity is accompanied by a mass 
of 7 smaller cells, which do not detach themselves tili the growth 
of the Ovum is completed. These smaller cells were regarded as 
Nährzellen by Vejdovsky ('78), but aecording to Chun's more recent 
and complete account ('88) the 7 smaller cells are to be regarded 
neither as Nährzellen nor as ultimately giving rise to ova. Waiving 
for the present any discussion of the function of these cells, I believe 
that they are undoubtedly the morphological equivalents of the ac- 
cessory cells of Myzostoma and the Nährzellen of Ophryotrocha. 
A very interesting case of the association of egg and Nährzellen 
has been observed by Andrews ('91) in Diopatra. In the ovary of 
this Polychaete the egg is attached to two long and tapering strings, 
each of which consists of a single series of compressed cells. The 
tapering tips of the strings are inserted in the ovaries, while their 
somewhat broader ends are attached either to opposite poles or later 
on to adjacent surfaces of the oocyte. »Eventually, such cell-loops 
(Fig. 5) break away even at the tips, and then float off in the body- 
eavity liquid, each with a growing centrally placed ovum .... The 
strings fall off after the ovum is 300 in diameter, and do not 
appear to diminish before then, but to drop off intact, though this 
lequires reinvestigation.« 
Spengel ('79) has given an excellent account of the growing 
egg of BonelUa. In this case the accessory cells which accompany 
the ovum during its growth are of three kinds: 1. a spherical mass 
of cells not unlike a blastula, and containing 2. a single centrai cell. 
This mass of cells, the »Zellenknopf«, is attached to one end of the 
