178 ALLAN' HAN-COCK PACIFIC EXPEDITIONS VOL. 25 



PLATE 20 



Upper. Part of tube mass of Dodecaceria fenvkesi Berkeley and Berkeley, 

 from Abalone Cove, near Marineland, California, at lowest tidal ex- 

 posure, seen from the exposed surface, x 1.2. 



Lower. Part of tube mass of Phragmatopoma calif ornica (Fewkes), 

 from Abalone Cove, near Marineland, California, in Mytilus zone, 

 exposed at normal low tide, x 1.1. 



