PLATE XXI. 



Rhabdammina. 



Diam. Page 



Figures 1-13. — Rhabdammina abyssorv/m, M. Sars, . . . 266 



Figs. 1-8. Specimens of various forms, 



Fig. 9. Fragment of a variety with branched arms 



(Rhabdammina irregularis, Carpenter?), 

 Figs. 10, 11. Specimens laid open to show the 



interior, . . . . x 10 



Figs. 12, 13. Surface more highly magnified, to show 



the constituent sand-grains; fig. 12, specimen 



from the equatorial Pacific; fig. 13, from the 



North Atlantic, . . ■ x • 60 



10 

 10 



