NO. 3 OSBURN : EASTERN PACIFIC BRYOZOA CYCLOSTOMATA 623 



Proboscina incrassata (Smitt), 1866 

 Plate 66, figs. 1 and 2 



Proboscina incrassata Smitt, 1866:402 and 458. 

 Tubulipora (Proboscina) incrassata Smitt, 1871:1119. 

 Alecto retiformis Hincks, 1871:81. 

 Stomatopora incrassata, Hincks, 1880:436. 

 Stomatopora incrassata, O'Donoghue, 1923:11. 

 Proboscina incrassata, O'Donoghue, 1926:17. 



The zoarium is white, adnate, much branched, the branches short, 

 anastomosing to form often a fairly close network; on the basal part the 

 branches are usually two tubules in width, but at the distal ends they 

 may be 4 to 6 tubules wide. The peristomes are very irregular in ar- 

 rangement, single or 2 or 3 in a transverse line; sometimes a few are 

 clustered but they are never connate except occasionally at the base; 

 sometimes also these clusters are elevated into short fascicles, especially 

 at the ends of branches. The peristomes are usually quite erect, 0.50 to 

 1.0 mm in height, 0.26 mm in diameter, and aperture about 0.20 mm. 



The ovicells, which seem not to have been noticed previously, are 

 simple ventricose expansions near the ends of branches and surrounded 

 by a row of tubules on each side (occasionally a peristome may be en- 

 closed in the expansion) ; the ooeciostome is a small erect tube much 

 shorter than the peristomes, terminal or nearly so, usually connate with 

 a peristome at its base but the tip always free, the aperture round and 

 about 0.13 mm in diameter. 



Described from Spitsbergen and recorded from Norway, Nova Zem- 

 bla, Kara Sea, and the British Islands from Cornwall to Scotland and 

 the Shetland Islands. On the Pacific coast O'Donoghue listed it for 

 several localities in British Columbia. Point Barrow, Alaska, Arctic 

 Research Laboratory, 328 feet, a common species, especially on stones, 

 G. E. MacGinitie, collector. 



Proboscina lamellifera Canu and Bassler, 1930 

 Plate 66, fig. 3 



Proboscina lamellifera Canu and Bassler, 1930:46. 



"The zoarium incrusts shells and is formed of sinuous branches joined 

 together by a smooth calcareous lamella. The tubes are indistinct, short, 

 seriated and terminated by a long peristome perpendicular to the zoarial 

 plane. Measurements, — diameter of orifice, 0.12 mm; diameter of 

 peristome, 0.16 mm; internal separation of tubes, 0.20 - 0.30 mm; width 

 of branches 1.5 mm." (Canu and Bassler, 1930:46). 



