ENTRY OF ZOOXANTHELLA INTO OVUM OF MILLEPORA. 709 
the nucleus. The substance of the manubrium has been for the greater 
part, encroached upon by the ova. x 120. 
Fie. 13.—A nucleus from an ovum of preceding figure. x 500. 
Fic. 14.—The nucleus of an extruded ovum, with a portion of the 
egg cytoplasm showing four zooxanthelle. In the central portion of 
the nucleus exists an aggregation of variously shaped chromatic bodies. 
x 500. 
Fie. 15.—Portion of an extruded ovum, showing two chromosome 
groups in a region of more compact cytoplasm. x 500. 
Fic. 16.—An unusually large extruded ovum, with islands of 
unvacuolated cytoplasm; two of these containing compact chromatic 
bodies, and a third more open chromatic strands. x 200. 
Fie. 17.—A liberated male medusa. The manubrium is surrounded 
by countless minute spermatids. On the umbrella are slight swellings 
bearing some large nematocysts. x 120. 
Fie. 18.—A zooxanthella, showing nucleus, pyrenoid, granules, and 
cell membrane. x 2000. 
