U. S. NATIONAL MUSEUM 



BULLETIN 100, VOL. 2, PART 3 PL, 21 



Fy./2. 



y 



FlpMA. 



fty/AB. 



Pyrosoma spinosum (Figs. II, A and B> and P. verticillatum (Fig. 12). 



For explanation of plate see page 270. 



