NO. 3 OSBURN : EASTERN PACIFIC BRYOZOA CYCLOSTOMATA 733 



Specimens in the Hancock collection are from off Point Barrow, 

 Alaska, Arctic Research Laboratory, collector, G. E. MacGinitie ; British 

 Columbia; and Dillon Beach, Tomales Bay, California. Depth range, 

 from intertidal to 36 fathoms. 



Flustrella gigantea Silen, 1947 



Plate 78, fig. 1 



Flustrella gigantea Silen, 1947:134. 



The zoaria are incrusting or arise into erect, flattened lobate, bilaminar 

 expansions measuring 3 to 4.5 cm in height, and 0.5 to 1.0 cm in width. 

 Macroscopically all the dark brown zoaria have a hirsute appearance 

 due to the presence of branching chitinous spines. The zooecia are 

 arranged in alternating series, varying in form from an irregular rec- 

 tangle to an uneven hexagon; in length they range from 0.97 to 1.25 

 mm, and in width from 0.70 to 0.83 mm. In younger portions of the 

 zoaria the zooecia are distinct, but in the older areas the lateral zooecial 

 walls are obscured by the pigmented cuticle. Each zooecium has a distal 

 raised oral papilla with the bilabiate aperture at its summit. The hollow 

 spines, arising from kenozooecia, are variable in morphology, and have 

 a location pattern that is only moderately uniform, Distally, about the 

 raised oral papilla on each zooecium, are 2 to 4 of the multibranched 

 spines. The number of terminal prongs may vary from 9 to 21, the most 

 frequent range being 11 to 14. Some spines, as well as having the normal 

 numerous prongs, are modified so as to have one large grossly extended, 

 thorn-like spike, giving the spine an over-all length of 1.38 to 2.05 mm. 

 This spectacular form of the spine is scattered at random in generous 

 quantity over the zoaria, from the growing tip to the most mature por- 

 tions of the zoaria. Sections revealed the tentacle number to be 26. 



The specimens described by Silen were from the Bering Sea. The 

 material in the Hancock collection is also from Arctic waters, off Point 

 Barrow, Alaska, G. E. MacGinitie collector. Depth, 36 fathoms. 



Family Pherusellidae Soule, new family 



Zoaria incrusting or arising into flattened flabellate, bilaminar exten- 

 sions. Aperture square or quadrangular, raised upon a stout tubular 

 process. Prominent compound communication pores (multiporous sep- 

 tulae), supported by heavy chitinous rings, connect adjacent zooecia, 

 piercing the distal as well as the lateral walls. No spines present. Prior 

 to this time the genus Pherusella has been placed under the family 



