NO. 3 OSBURN : EASTERN PACIFIC BRYOZOA CYCLOSTOMATA 711 



The zoarium is usually rounded, attached more or less over the whole 

 dorsal surface but sometimes only by a very short stipe, surrounded by 

 a moderate bordering basal lamina which is sometimes turned slightly 

 upward ; the central part of the colony in young stages is a little de- 

 pressed and with rounded cancelli which become partially closed. Adult 

 colonies, with brood-chambers, are usually evenly rounded over the top. 

 The tubules vary much in their arrangement, sometimes occurring in 

 radiating uniserial rows in which, however, the tubes are not connate, 

 or at least are free at their tips; for the most part they are irregularly 

 quincuncial, and they are separated by rounded cancelli about as large 

 as the apertures of the zoids, about 0.08 mm in diameter. The peristomes 

 are a little elevated, rising on the central side into a pointed cusp which 

 is sometimes double or tricuspidate. 



The ovicells, or brood-chambers, are located at the edges of the central 

 area and extend outward between the zooecial tubes ; occasionally, when 

 more than one is present (I have noted as many as 4) their expanded 

 inner ends may cover the central area. The ooeciostome is situated at 

 the edge of the central area or farther out between the tubules, short, 

 cylindrical, with a round aperture which is somewhat larger than that 

 of the tubules, about 0.10 mm in diameter. The chamber at first is cov- 

 ered by a thin, minutely perforated calcified layer, but later this may 

 secondarily be covered with a cancellous layer. 



It is a well known northern and arctic species, extending on the 

 Pacific coast south to Lower California. 



Hancock Stations: 1260-41, off San Eugenio Point, Lower California, 

 27°49'50"N, 115°06'05'"W, the southernmost record; oflf Santa Cata- 

 lina, Santa Barbara and San Miguel Islands, and Albatross Sta. 2938, 

 all from southern California; from near shore to 34 fms. Also a speci- 

 men labelled "Bering Sea," with no other data. 



Disporella calif ornica (d'Orbigny), 1853 /--O 



Plate 74, figs. 7, 8, and 9 



Unicavea Californica d'Orbigny, 1853:972. 



Not Lichenopora californica, Gabb and Horn, 1862:176. 



Not Discoporella calif ornica. Busk, 1875:32. 



Not Lichenopora calif ornica. Waters, 1889:282. 



Not Lichenopora californica, Robertson, 1910:261. 



Lichenopora californica, Borg, 1944:219. 



D'Orbigny's description, without illustration, reads: "Espece tres- 

 convexe en dessus, ayant le centre excave, et pourvue de pores inter- 

 mediares enormes. Madelaine, Basse-Californie." 



