NO. 2 OSBURN: eastern pacific BRYOZOA — CHEILOSTOMATA 403 



with a raised separating line. The frontal is slightly elevated, with numer- 

 ous large and evenly distributed pores. The pores expand upward to form 

 large infundibuliform pits separated at their rims by narrow walls which 

 produce a coarsely reticulated surface over the whole front. The primary 

 aperture is like that of S. landsborovii (about 0.20 mm wide by 0.18 mm 

 long), with distinct cardelles, but the lyrula is much smaller, seldom as 

 much as one-fourth of the width of the aperture. The secondary aperture 

 is also of the same pattern but is more elevated, especially at the proximal 

 border where it completely surrounds the more elevated avicularium. 

 The avicularium chamber is small (appearing to be entirely median but 

 dissection shows a narrow tube on each side extending to a lateral pore) ; 

 the rostrum elevated, narrow and longitudinally ribbed nearly to its 

 tip ; the mandible is semicircular. 



The ovicell is comparatively small (about 0.25 mm wide), rounded 

 and prominent, smooth or slightly roughened, with a single large rounded 

 pore on the top (more rarely there are two or even three smaller pores). 



Type, U. S. Nat. Mus., 11030; paratype AHF no. 83. 



Type locality, Leonard Harbor, Alaska, 20 fms, Alaska Crab Investi- 

 gation station 60-40, several colonies. Also at Canoe Bay, Alaska, shore, 

 station 12-40. 



Smittina bella (Busk), 1860 

 Plate 47, figs. 4-5 



Lepralia bella Busk, 1860 :144. 



Smittina bella, Osburn, 1923 :10D ; 1933 :49. 



The zoarium forms flat, smooth and rather regular incrustations on 

 stones and shells. The zooecia are of moderate size, about 0.55 to 0.70 mm 

 long by 0.35 to 0.50 mm wide, arranged quite regularly. The frontal 

 is a tremocyst with moderately large pores, slightly inflated in the young 

 marginal zooecia but becoming quite flat with age so that the zooecial 

 borders are indefinite. The primary aperture (marginal zooecia) is nearly 

 round, straight on the proximal border where there is a short, narrow, 

 truncate lyrula; the cardelles small and low. The primary peristome is 

 low and thin and soon becomes completely obscured by the thick frontal 

 wall which forms the secondary aperture ; this is more or less pyriform, at 

 the level of the general crust, and encloses the small median suboral avicu- 

 larium with a semicircular mandible. In very young marginal zooecia 

 the avicularian chamber is lunate and extends across the front from one 

 areolar pore to another on the opposite side, but the chamber soon becomes 



