326 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



Dakaria apertura new species 

 Plate 39, figs. 7-9 



Zoarium encrusting rocks and shells. The zooecia are large, 0.65 to 

 0.90 mm long by 0.45 to 0.60 mm wide, arranged in series when free- 

 growing, distinct with well-marked grooves ; the frontal somewhat ventri- 

 cose, a thick tremocyst with large infundibular pores, granular in older 

 stages and often with a broad umbonate swelling on the distal half; 

 covered with a thick ectocyst. The primary aperture is nearly round, 

 width 0.20 to 0.23 mm, length, 0.18 to 0.22 mm; the anter a little 

 more than a semicircle back to the prominent cardelles between which 

 the poster extends in an arc similar to and only slightly narrower than 

 that of the anter. The operculum has the form of the aperture, rather 

 heavily chitinized and, except in young zooecia, whitish in color with a 

 light brown border ; there is a complete bordering sclerite, with the muscle 

 attachments near the margin. The peristome is low and thin, the sec- 

 ondary border not elevated but often rough, especially on the proximal 

 border where it joins the low umbonate swelling. 



The ovicell is large, 0.50 to 0.60 mm wide, not deeply embedded, the 

 front somewhat depressed and perforated with irregularly shaped pores 

 of different sizes; in full calcification a heavy and very rough border 

 extends up the sides of the ovicell but leaves a broad rounded perforated 

 area. 



The large size, longer aperture with larger poster, the nature of the 

 ovicell and the presence of the broad umbonate process distinguish the 

 species. 



Type, AHF no. 64. 



Type locality, Tomales Bay at Dillon Beach, California, about 

 38°15'00"N at 6 fms, R. J. Menzies, collector, several colonies. 



Dakaria dawsoni (Hincks), 1883 

 Plate 39, figs. 1-2 



Schizoporella dawsoni Hincks, 1883 :449. 



Schizoporella torquata Hincks, 1884:41 (not Escharina torquata 



d'Orbigny). 

 Schizoporella dawsoni, O'Donoghue, 1926:56. 



Zoarium encrusting, multilaminar, white to yellowish or reddish- 

 brown. Zooecia moderately large, 0.55 to 0.75 mm long by 0.35 to 

 0.50 mm wide, quite variable in size and arrangement in the secondary 

 layers ; considerably inflated and distinct in younger zooecia, with a raised 

 separating line in older specimens. The frontal is a tremocyst with numer- 



