398 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



The species differs in the complete absence of a lyrula and in the 

 spreading form of the secondary aperture which is widest at the proximal 

 end. 



Type, AHF no. 82. 



Type locality, Station 1190, Cortez Bank, just south of the United 

 States-Mexican boundary, 32°24'00''N, 119°02'30nV, 131 fms. Other 

 stations: 1187-40 and 1224, Santa Catalina Island; 1190-40, Anacapa 

 Passage; 1294-41 and 1299, Santa Cruz Island, all from southern Cali- 

 fornia; 2160, San Benito Islands west of Lower California; 270, Angel 

 de la Guardia Island, Gulf of California; 328, Cocos Island off Costa 

 Rica; and Wenman Island, Galapagos. Bathymetric distribution 14 to 

 150 fms. 



Porella columbiana O'Donoghue, 1923 



Plate 46, figs. 7-8 



Porella columbiana O'Donoghue, 1923 :41. 

 Smittina columbiana, O'Donoghue, 1926 :69. 



Zoarium encrusting in a thin, glistening layer. The zooecia are mod- 

 erate in size, 0.45 to 0.55 mm long by 0.25 to 0.35 mm wide, rather 

 regularly arranged ; the frontal ventricose, thin and more or less hyaline 

 in younger stages, somewhat thicker and white when fully calcified ; the 

 areolar pores are large and conspicuous at all stages, with short costae 

 which extend toward the center. The primary aperture is slightly wider 

 than long, rounded distally and nearly straight on the proximal border 

 which bears a very low inconspicuous lyrula; the cardelles are minute 

 and often wanting. The peristome is high, especially on the sides, encloses 

 the suboral avicularium proximally and bears 2 or 4 small spines on the 

 low distal border ; it fuses with the ovicell of fertile zooecia at the sides 

 but does not develop across the front. The avicularian chamber is con- 

 siderably inflated in young zooecia, bears about 3 small areolar pores 

 and becomes more or less immersed with age ; the rounded rostrum rises 

 above the chamber and projects slightly over the aperture, bearing a 

 semicircular or slightly triangular mandible. No frontal avicularia. 



The ovicell is at first rounded, hyaline and shining, about 0.18 mm 

 broad ; with increased calcification a broad collar develops around the 

 base, and a thin-walled area is usually present on the top. 



Described and listed by O'Donoghue from a number of localities in 

 British Columbia. 



