240 THE AMERICAN NATURALIST. (VoL. XXXIX. 
other cytoplasm of the sperm at the end of the. egg, passes 
quickly to the center to unite with the female nucleus. The 
blepharoplast remains near the periphery of the egg and may be 
recognized even after the gamete nuclei have united. It finally 
breaks down and its substance becomes lost in the cytoplasm of 
the egg. The most complete account of the history of the ble- 
pharoplast in the fertilized egg is that of Webber (:01). We 
should naturally expect the first cleavage spindle in the cycads 
and Ginkgo to be developed as in the conifers. Ikeno (:O1) 
described clearly an intranuclear spindle in Ginkgo. In the 
conifers, as previously described, the first cleavage spindle is 
intranuclear and the fibers are developed freely from a mesh 
and form a broad poled spindle without centrospheres. So that 
not only does the blepharoplast break down at a distance from 
the egg nucleus but we have no reason to think that there is 
any place for a centrosome in the history of the first cleavage 
spindle in the gymnosperms. 
We do not know clearly the fate of the blepharoplast in the 
egg of any pteridophyte or bryophyte, although Shaw's (98a) 
studies on Onoclea indicate that it breaks down in the cyto- 
plasm. Our knowledge of the thallophytes is equally incom- 
plete as regards the history of the blepharoplast in the egg. 
But both Strasburger ('97a) and Farmer and Williams (98) 
have agreed for Fucus that the two centrospheres at the poles 
of the first cleavage spindle develop de novo and independently 
of one another, and Williams (: 04b) holds the same view for the 
centrosphere which appears at the side of the fertilized egg of 
Dictyota. The sperms of the thallophytes are generally very 
small cells and it may prove a difficult matter to follow their 
blepharoplasts so that our opinions of events in these forms! are 
likely to be largely inferential from our knowledge in higher 
groups. 
We can safely say that there is no evidence that the blepharo- 
plast ever enters into the first cleavage spindle which is certainly 
developed in the spermatophytes and probably in the pterido- 
phytes without centrosomes or centrospheres. 
somes or centrospheres are known for the first cl 
in the thallophytes (Fucus and Dictyota), 
Where centro- 
eavage spindle 
the observations indi- 
