180 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



border. On either side of the aperture is a short, broad spine which is 

 sometimes bifurcate, often merely pointed and frequently wanting. There 

 are no avicularia. 



The ovicell is prominent, 0.25 to 0.30 mm broad, sometimes longer 

 than broad and a little pointed at its distal extremity, with a low broad 

 keel and with larger pores around the border and smaller ones on the top. 



Described by Hincks from Cumshewa and Houston-Stewart Chan- 

 nel, and listed by O'Donoghue from numerous other localities in British 

 Columbia. 



Hancock Stations: 1119-40, off San Benito Islands, west coast of 

 Lower California, and 1303-41, Santa Cruz Island, off southern Cali- 

 fornia. Also at Middle Bank, Puget Sound, Dr. J. L. Mohr, collector. 

 Shallow water to 87 fms. 



Reginella mucronata (Canu and Bassler), 1923 

 Plates 28, fig. 4 and 29, fig. 3 

 Metracolposa mucronata Canu and Bassler, 1923-926. 



Zoarium encrusting, usually on stones and shells. The zooecia are 

 ventricose and prominent, sharply set off from each other by deep grooves. 

 The frontal shield or pericyst is formed by the fusion of 5 or 6 pairs of 

 rather regularly arranged costae which meet at the midline either 

 smoothly or with a low median keel. Each costa bears two small rounded 

 lumen pores and between the costae there are 5 or 6 rounded or somewhat 

 slit-like pores (lacunae). The pair of costae which form the proximal 

 border of the aperture are elevated into a bimucronate lip. There are no 

 spines, no avicularia and no dietellae. Zooecial length, average, 0.50, 

 width 0.35 mm. 



The ooecium is large and conspicuous, 0.26 to 0.30 mm wide, rather 

 deeply embedded and bears a variable number of pores, irregularly dis- 

 tributed, the marginal ones being somewhat larger. Often a carina is 

 present and the area just distal to the aperture may be flattened on each 

 side and irregularly striated longitudinally. The ooecium is usually notice- 

 ably longer than broad, but in crowded areas the reverse may be true. 



Canu and Bassler described M. mucronata from 'Tleistocene: Santa 

 Barbara, California, (rare)." I have not been able to find any constant 

 difference between recent and fossil material. The original description 

 does not mention the pores of the ovicell, but fossil specimens sent me by 

 Dr. Bassler show the character of the pores, usually occluded by fossiliza- 

 tion. The variations in measurement transcend in both directions those 

 of Canu and Bassler. 



