BULL. U. S. F. C. 1900. HARGITT & ROGERS. 
PLATE IV. 
FIG. 1, COLONY OF PLEXAURA CRASSA. FIGS.2TO 12, SPICULES OF SAME. FIG. 2, WHITE, 
0.36X0.17 MM; FIG. 3, 0.34 X 0.219 MM; FIG. 4, 0.469 X 0.149 MM; FIG. 5, 0.45 X 0.25 MM; 
FIG. 6, 0.34 X 0.24 MM; FIG. 7, 0.265 X 0.1 1 7 MM; FIG. 8, 0.14 X 0.1 17 MM; FIG. 9, RED, 
0.13X0.09 MM; FIG. 10, RED, 0.125 X 0.09 MM; FIG. 1 1 , WHITE, 0.72 X 0.1 MM; FIG. 12, 
RED, 0.33X0.19 MM; 
FIG. 13, COLONY OF PLEXAURA FLEXUOSA. FIG. 14, RED THORNY SPINDLE, 0.36 X 0.093 
MM; FIG. 15, RED WARTY SPINDLE, 0.86 X 0.20 MM; FIG. 16, WHITE WARTY SPINDLE, 0.83 
X 0.19 MM. 
HEUOTYPE PRINTING 00., BOSTON. 
