114 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



dant; represented in the Hancock collections at 151 stations from the 

 northern Channel Islands, California, to Santa Elena Bay, Ecuador, the 

 Galapagos Islands, Colombia, Panama, Costa Rica, Mexico, and the Gulf 

 of California. Dredged from 5 to 100 fms, but most abundant at 20 to 

 40 fms. 



Family Aspidostomidae Canu, 1908 



"The zooecia have a raised margin, often indistinctly or incompletely 

 developed. The two opesiules appear as narrow^ incisions w^hich join the 

 zooecial aperture ; the short polypide tube, which is not continued under 

 the cryptocyst cover, is in most cases provided with marginal flanges. 

 Avicularia are always present. Ovicells are hyperstomial" (Canu and 

 Bassler 1920:252). 



The one genus here included, Euritina, differs from the above de- 

 scription in having very minute opesiules which are scarcely noticeable 

 at the proximal corners of the opesia, and in the one species recorded no 

 avicularia have been found. The other characters are similar to those of 

 the family. 



Genus EURITINA Canu, 1900 



"Ovicell hyperstomial, never closed by the opercular valve; aviculari- 

 um interzooecial ; cryptocyst well developed, with three facets separated 

 by two longitudinal grooves; no dietellae" (Canu and Bassler, 1920: 

 256). Genotype, Eschara eurita d'Orbigny, 1852. 



Euritina arctica new species 

 Plate 29, figs. 5 and 5a 



Discopora ( ?) impressCj Smitt, 1871 :1126. 

 Not Escharina impressa Reuss, 1846 :68. 



Encrusting, unilaminar, white to brown in color. Zooecia moderately 

 large, 0.60 to 0.70 mm long by 0.40 to 0.50 mm wide, but these limits 

 are transcended in both directions ; regularly arranged in quincunx, very 

 distinct, irregularly ovate, the distal end rounded or ogival, the proximal 

 end usually narrowed between adjoining zooecia. The front wall is a 

 heavy cryptocyst with three areas, a broad rounded lateral area on each 

 side and a central area which occupies half or more of the width and is 

 separated on each side by a shallow groove which runs forward to the cor- 

 ner of the aperture ; the central area slopes downward to the level of the 

 aperture. The whole surface of the cryptocyst, even the whole margin of 



