NO. 2 OSBURN: eastern pacific BRYOZOA — CHEILOSTOMATA 349 



and the distal end somewhat elevated, arranged in quincunx; in the 

 secondary layers the zooecia are partially erected and turned in every 

 direction. The frontal is a pleurocyst with a row of areolar pores (often 

 difficult to see and occasionally there are a few additional pores), smooth 

 or granulated in the young but becoming exceedingly irregular with 

 ridges and high tubercles. Normally there is a pointed umbonate process 

 proximal to the aperture and one on each side (sometimes spine-like) and 

 often there are others on the frontal. The aperture is lepralioid, rounded 

 in front of the strong cardelles, broadest proximal to the cardelles and 

 broadly arcuate, about 0.12 by 0.12 mm. The vestibular arch is often 

 delicately beaded. The primary peristome is low and thin, with 2 to 4 

 small spines; with secondary calcification the spines disappear and the 

 peristome is covered by the encroaching frontal wall. As indicated by 

 Hastings, there are two kinds of opercula, one with sinuous sclerites 

 and the other with thick bordering sclerite which is produced downward ; 

 muscle attachments are at the distal ends of the sclerites. The avicularia 

 vary exceedingly; often there is a small rounded one asjnmmetrically 

 situated at the base of the umbo and included in the secondary aperture, 

 the lateral processes may be replaced by small round or pointed avicu- 

 laria, and frontal avicularia, round or pointed, large or small, may 

 occur on the frontal. 



The ovicell is hyperstomial, not closed by the operculum, broader 

 than long (0.18 to 0.20 mm wide), prominent, smooth and imperforate 

 when young but soon covered and embedded by the rough ectocyst and 

 surrounding frontal walls. 



The species was described by Hastings from Gorgona, Colombia, and 

 recorded also from Taboga, Jicaron and Coiba Islands, oflF Panama, and 

 from the Galapagos Islands. 



Hancock Stations: recorded from more than 30 stations, all the 

 way from southern California to the Galapagos Islands; Santa Cruz, 

 Santa Rosa and Santa Catalina Islands and off the San Pedro break- 

 water, southern California; Angel de la Guardia Island, Gulf of Cali- 

 fornia > west coast of Mexico ; Socorro Island ; Costa Rica ; Panama ; 

 Colombia ; Ecuador ; and Wenman, James, Albemarle and Hood Islands, 

 Galapagos. The known geographic range is from about 34°N to a little 

 south of the equator, and the depth range from shore to 82 fms. 



