No:3:]] ALLOLOBOPHORA FOETIDA. 501 
spine (the anterior end of the head of the spermatozoén), I 
have made the following observations on this point. I have 
seen very early stages of the development of the sperm attrac- 
tion-sphere, — stages where the middle-piece of the sperm is 
still intact, while the rays of the attraction-sphere are focused 
around it, just as the rays of the cone are at one stage focused 
around the head of the spermatozodn. I hope to be able to 
illustrate the morphological resemblance of these two struc- 
tures in a series of photomicrographs. 
Cytoplasmic Granules or Microsomes.—In an earlier paper 
(7) I published a list of structures in these eggs, which select 
methyl green, among them numerous “ large and small granules 
or bodies,” also the centrosomes and nucleoli. I have since 
succeeded in differentiating from these structures the cen- 
trosomes and the nucleoli, the latter being found in the cyto- 
plasm of the odcytes, Ist and 2d orders, as well as in the 
pronuclei. The details of this work will be published later. 
Spindle.---The phenomena in this egg indicate that at 
least part of the first cleavage spindle has its origin in the 
cytoplasm ; as the polar rays are often formed while the mem- 
brane of both pronuclei is intact. When an isolated male 
pronucleus has reached its maximum size, its attraction- 
sphere is seen in the cytoplasm, while the membrane of the 
pronucleus is still intact. Occasionally a spindle is formed 
by the meeting of the rays of two male attraction-spheres, or 
the rays of a male attraction-sphere with those of the egg 
attraction-sphere at the lower pole of the second maturation 
spindle. All these rays anastomose, as do the fibers in the 
first and second maturation spindle.! 
Reduction. —Twenty-two chromosomes can be counted in 
the odgonia and only eleven in the first maturation spindle ; 
thus we have the typical number reduction of chromosomes, — 
the ‘“pseudo-reduction” of Riickert (17). The position and 
shape of the chromosomes in the spindle accord with Flem- 
ming’s (4) heterotype form of division. In many cases four 
distinct parts can be differentiated (text Fig. 4), the typical 
tetrad being thus represented. At the beginning of the anaphase 
1 For figures of these spindles, see Foot (5), Figs. 1 and 3; (8), Fig. 4. 
