NO. 3 OSBURN : EASTERN PACIFIC BRYOZOA CYCLOSTOMATA 625 



Zoarium a flat fan-shaped or lobulate incrustation on shells and stones ; 

 moderately thick, usually with two rows of incomplete zooecia bordering 

 the outer functional ones. The zooecial tubules are elongate and hori- 

 zontal for most of their length, about 0.30 mm wide, convex and the 

 separating grooves distinct, finely punctured. The peristomes are short, 

 suberect, quincuncial in arrangement, the aperture about 0.15 mm in 

 diameter. 



The ovicells resemble the zooecial tubules, elongate, pointed at the 

 proximal end, only a little swollen and more thickly punctate ; they were 

 overlooked for many years, probably because of their resemblance to the 

 tubules, but they are definite enough when one knows what to look for. 

 The ooeciostome is terminal, short, erect, round and about 0.08 mm in 

 diameter, not associated with a peristome. 



Described from the Shetland Islands by Norman and recorded also 

 by Hincks from the British Islands. On the west coast of the North 

 Atlantic it ranges from Cape Cod northward to Mount Desert Island, 

 Maine, to the Gulf of St. Lawrence and Baffin's Bay. 



Point Barrow, Alaska, Arctic Research Laboratory, G. E. Mac- 

 Ginitie, collector; also at Canoe Bay, southern Alaska, U. S. Alaska 

 Crab Investigation, Sta. 25-40 at 25 fms. 



Oncousoecia canadensis Osburn, 1933 



Plate 65, figs. 10 and 11 



Oncousoecia canadensis Osburn, 1933:12. 

 Stomatopora diastoporides, Whiteaves, 1901:110. 



The zoarium is flabellate or irregularly lobate, entirely adnate on 

 shells and stones, the primary region, 2 or more tubules in width, is 

 usually short ; thinner than in O. diastoporides. The tubules are com- 

 paratively thin-walled, somewhat hyaline and vitreous, conspicuously 

 perforated. They are more slender than those of diastoporides (width 

 about 0.18 mm), and never does more than one row of incomplete ones 

 appear at the margin. The peristomes are short, thin-walled, the aper- 

 ture about 0.10 mm in diameter, and never connate nor seriated. 



The ovicells are usually like small thin-walled blisters; the fertile 

 zooecium arises in the same manner as the infertile ones but soon ex- 

 pands both frontally and laterally and the adjacent tubules appear as if 

 separated by the growth of the expansion. Sometimes the expansion 

 extends in very short lobes on either side of the ooeciostome, but occa- 

 sionally it may be as simple as in diastoporides. The ooeciostome is 



