NO. 3 OSBURN : EASTERN PACIFIC BRYOZOA CYCLOSTOMATA 729 



previously reported by Robertson, 1900, and O'Donoghue, 1923, 1926, 

 in the waters off Alaska, British Columbia, and Puget Sound. 



The specimens in the Hancock collection are from off Point Barrow, 

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

 Lenard Harbor, Alaska, Canoe Bay, Alaska, Tomales Bay, California, 

 AHF stations 1607-48 and 1656-48 in depths ranging from intertidal 

 to 40 fathoms. (8 stations.) 



Alcyonidium parasiticum (Fleming), 1828 

 Plate 77, fig. 2 



Alcyonium parasiticum Fleming, 1828:518. 

 Alcyonidium parasiticum, O'Donoghue, 1923:191. 



The collection has one large zoarium, thin, incrusting upon an eroded 

 mollusk shell. The individual zooecia may be distinguished with some 

 difficulty, due to the deposit of sand and mud which covers most of the 

 zoarium. The zooecia are small, irregular in morphology, the variation 

 ranging from nearly square zooecia to those that are elongated to nearly 

 diamond-shaped. All of the zooecia that could be examined possessed 

 raised oral papillae on the ventral surface, and minute border papillae. 

 The argillaceous cover upon the cuticle prevented sectioning of a portion 

 of the specimen. 



This species is well distributed throughout the colder Atlantic waters 

 and has been reported by O'Donoghue from the Pacific northwest. 



The specimen in the Hancock collection came from Tomales Bay, 

 California, at a depth of 5 fathoms, collector R. C. Osburn. 



Alcyonidium mammillatum Alder, 1857 

 Plate 77, fig. 4 



Alcyonidium mammillatum Alder, 1857:154. 



Alcyojiidium mamillatum, O'Donoghue, 1923:191; 1926:54. 



The zoaria form dark brown, thin, rough, irregular incrustations 

 upon mollusk shells. The zooecial walls are well defined, except in the 

 portions of the zoaria that are covered by foreign matter. The zooecia 

 vary in shape from an elongated irregular oval to rectangular. Distally 

 the zooecial apertures are raised upon short cylindrical, transversely 

 wrinkled projections. 



The literature reveals that this species is moderately well known from 

 the cold waters of the Atlantic. On the Pacific coast of North America, 

 O'Donoghue has reported it from the vicinity of Vancouver Island, 1923, 

 1926. 



