NO. 3 OSBURN : EASTERN PACIFIC BRYOZOA — CYCLOSTOMATA 681 



ovigerous colonies frequently bear the pointed tips and their branches 

 may be perfectly straight. Sex differentiation does not seem to be the 

 answer to these variations. 



Trask described the species from San Francisco, very inadequately. 

 Miss Robertson accepted the name and redescribed the species, recording 

 it from Puget Sound, Washington, to San Pedro, California. O'Donog- 

 hue listed it from Banks Island and Gabriola Pass, British Columbia. It 

 is a common species along the California coast from low water to 30 

 fms, and south rarely to the Galapagos Islands. 



Hancock Stations: Dredged at 12 stations, mostly about the islands 

 ofl southern California. Station 470-35, Port Parker, Costa Rica, 5 

 fms, and 85-33, North Seymour Island, Galapagos, shore collection. 

 The number of the dredging stations does not indicate the abundance 

 of the species, as it is much more common in shallow water near shore. 



Grisia operculata Robertson, 1910 

 Plate 71, figs. 6 and 7 



Crisia operculata Robertson, 1910:240. 

 Crista operculatdj O'Donoghue, 1923:7. 



The zoarium is fragile, with irregular tufts reaching a height of 

 about 20 mm; internodes consist of about 10 to 20 zooecia, though the 

 number may reach 30 or more; the frontal surface rounded but not 

 keeled, the basis rami exposed for most of its length. The zooecia are 

 very slender, connate for most of their length, though the free tips are 

 longer than in most crisias. The distance between the zooecial apertures 

 is considerably greater than the width of the internode. 



Ovicell elongate pyriform, inclined to one side of the internodal axis; 

 "the dorsal wall of the ooecium extending upward and forward covering 

 the ooeciostome as with a lid or cap, the operculum" (Robertson). The 

 ooeciopore is a semicircular slit beneath the cap. 



The species was described from "one station on the southern Cali- 

 fornia coast, depth not known." O'Donoghue recorded it from Houston 

 Passage, British Columbia, 15 fms. 



Hancock Stations: dredged at only 4 stations: 1378-41, Santa Cata- 

 lina Island, southern California, 2-3 fms; 1049-40, Angel de la Guardia 

 Island, Gulf of California, shore ; 675-37, Pulpito Rock, Gulf of Cali- 

 fornia, 55 fms, and San Francisco Island, Gulf of California, 47 fms, 

 24°47'35"N, 110°35'55'''W, the most southern record. Apparently it 

 is not a very common species. 



