NO. 1 OSBURN : EASTERN PACIFIC BRYOZOA CHEILOSTOMATA 81 



cal or oval in form. The frontal membrane is thick and brownish, the 

 operculum heavily chitinized and 0.20 mm or more in breadth. 



The usual complement of spines is 4 on each side, very evenly spaced, 

 stout and erect or nearly so ; the second pair, opposite the operculum, are 

 somewhat taller and much stouter than the others. No avicularia are to 

 be found on the several colonies studied. 



The ovicell is of striking appearance, even for a Tegella : very promi- 

 nent, somewhat transverse (0.30 mm wide by 0.25 mm long), thick and 

 heavily calcified, with a thick, elevated rim on the top surrounding a 

 large, irregularly rounded area which is covered by a membrane, and 

 frequently the distal side of the rim rises into a point. The endooecium 

 is smooth, thin and only slightly calcified and is not perforated, and it is 

 not fused with the outer layer. The ectooecium is very irregular in 

 complete calcification and the area varies in form from perfectly circular 

 to transversely or longitudinally elliptical, or it may be more or less 

 irregularly rounded. On the distal aspect of the ooecium there is another 

 rounded fenestra in the position usually occupied by an avicularium in 

 this genus, but it is covered by a smooth membrane. 



There are large multiporous rosette plates in the lateral and distal 

 walls. 



By the definition of the genus Tegella, the ovicell is surrounded by 

 an avicularium. In the present species there is no evidence of an avicu- 

 larian mandible, but the distal fenestra referred to may possibly be in- 

 terpreted as the vestige of an avicularium. In other characters the species 

 appears to agree in all respects. 



Type, AHF no. 20. 



Type locality, Canoe Bay, Alaska, 125 fms on dead shells, several 

 colonies. Also at Point Barrow, Alaska, Arctic Research Laboratory, 

 G. E. MacGinitie, collector. 



^f y> Tegella robertsonae O'Donoghue, 1926 



Plate 9, fig. 5 



Membranipora unicornis, Robertson, 1900:324. 



Membranipora occultata Robertson, 1908:262 (not M. occultata Wat- 

 ers). 

 Membranipora occultata, O'Donoghue, 1923 :25. 

 Tegella robertsoni O'Donoghue, 1926 :36. 



Zoarium encrusting shells, sponges and larger algae. Zooecia moder- 

 ate in size, 0.55 to 0.65 mm long, distinct only in young stages. Gymno- 

 cyst well developed, usually about one-third of the frontal length ; crj'pto- 



