NO. 2 OSBURN: eastern pacific BRYOZOA CHEILOSTOMATA 331 



Schizomavella auriculata (Hassall), 1842 

 Plate 38, fig. 5 



LepraUa auriculata Hassall, 1842:411. 

 Schizoporella auriculata, Hincks, 1880 :260. 

 Schizoporella auriculata, Robertson, 1908:286. 

 Schizoporella auriculata, O'Donoghue, 1923 :34 ; 1926 :58. 



Zoarium encrusting, especially on shells. Zooecia rather small, aver- 

 aging about 0.45 mm long by 0.35 mm wide but varying greatly, more or 

 less quadrate or rhomboid ; the frontal a tremocyst with small pores, 

 moderately convex, distinct with a separating line, smooth or granulated. 

 The primary aperture is round back to the level of the cardelles, with 

 a rather shallow sinus, the length and width about equal and varying 

 from 0.10 to 0.12 mm in either dimension. Peristome low and smooth. 

 A small avicularium, usually mounted on a small umbo, is situated 

 in the midline proximal to the sinus, the mandible varying from semi- 

 circular to short spatulate. 



The ovicell is comparatively large, about 0.25 mm broad, hyper- 

 stomial, perforated, the front slightly flat. 



The species is unusually variable and scarcely any two colonies are 

 exactly alike. 



Recorded by Robertson from the Coronado Islands just south of 

 the United States-Mexican boundary, and by O'Donoghue from several 

 localities in British Columbia. It is a common North Atlantic species. 



Hancock Stations: Dredged at numerous stations from the coast 

 of Oregon south to San Benito Islands and Dewey Channel on the 

 west coast of Lower California and Isla Partida in the Gulf of Cali- 

 fornia; common about the islands off southern California, but not 

 noted south of 29° N Lat. 



Schizomavella auriculata ochracea (Hincks), 1880 

 Plate 38, fig. 6 



Schizoporella auriculata Yzr. ochracea Hincks, 1880:262; 1884:16. 

 Schizoporella auriculata ivhsY>- ochracea, Robertson, 1908:286. 

 Schizomavella auriculata \zr. ocArac^o, O'Donoghue, 1926:59. 



This variety is characterized by the avicularium which is submersed 

 and lies flat in the frontal instead of elevated ; it is also usually farther 

 removed from the aperture ; its mandible may be rounded or subspatulate. 

 Other characters are similar to the typical form. 



