27a JOHNSON. [Vou. IX. 
meaning of any particular instance of plastogamy must of 
course be arrived at, not alone from investigation of the proc- 
ess itself, but from a study of the phenomena preceding and 
following it. 
While at Clark University in the winter of 1891-92, I had 
an opportunity to study the well-known coalescence of distinct 
Series to illustrate the plastogamy and subsequent division of two Actinos- 
pheria. Median optical sections, X 27. Fig. 4, before the fusion of the endo- 
plasms ; Fig. 2, 45 minutes later; the endoplasms have partially fused; Fig. C, 
completion of plastogamy, 1 hour 5 minutes later than B; Fig. D, division, 3 
hours 45 minutes later than C. Division afterwards completed, and the enlarged 
portion Y in the commissure became a separate individual. Zc., ectoplasm; 
£n., endoplasm. 
