500 M. D. HILL. 
and then disappears, leaving no trace of its presence. The 
deeply staining yolkless protoplasm, referred to as being 
possibly a modified archoplasm, also vanishes. The egg is 
now without any nucleus, and in this state leaves the polyp. 
Unless fertilised it remains “anucleate ” until it dies. ‘The 
death of the ovum is indicated by its sinking to the bottom, 
and assuming irregular shapes. Such an egg, if kept ina 
small glass jar on the laboratory table, will soon die (18-24 
hours). In the tanks it will float for a day or two. In this 
9 pron. 
Fic. 5.—Female pronucleus nearly disappeared, (?) male pronucleus. 
state were most of the eggs I examined, but owing to the 
difficulty of getting ripe male colonies, comparatively few 
eggs were fertilised. 
Professor Hickson, however, was more successful than I, 
for in 1893-1894 and in 1897-1898 he succeeded in getting 
many ege’s to segment. He found, however, a similar diffi- 
culty in obtaining male colonies, and believed that most of 
the eggs were fertilised by floating spermatozoa in the tank- 
water. 
