EXPLANATION OF PEATE Sx, 
FIGURE 257.—Alcyonidium ramosum, (p. 708 ;) a young unbranched specimen, enlarged 
two diameters. 
258.—Bugula turrita, (p. 712;) extremity of a branch, enlarged. 
259.—The same; a branchlet more highly magnified. 
259a.—The same; a branchlet bearing ovicells. 
260.—Crisia eburnea, (p. 707;) a cluster of branches, enlarged. 
261.—The same; a branch bearing an ovicell, more highly magnified. 
262.—Membranipora pilosa, (p.712;) a few of the cells, seen from above, 
magnified. 
262a.—The same; a single cell, seen in profile. 
263.—The same; one of the zodids expanded. 
264.—Mollia hyalina, (p. 713 ;) one of the zodids in expansion, highly magnified. 
{Figures 257, 259, 259a were drawn by A. E. Verrill; the rest were furnished by A. Hyatt.) 
