1908] Robertson. — Incrusting Bryozoa. 313 



often inclined toward eaeli other; mandible directed slightly away 

 from the orifice; avicnlaria frequently lacking except on zooecia 

 that bear ocx'cia. Ooecia, oe., small relatively to the size of the 

 zo(pcia, recumbent, rounded, smooth, broader than high, a trian- 

 gular- i)ortion. tri. por., in the front which is very transparent 

 and thin, and frequently broken away, thus making the oral arch 

 appear very high. 



This species reported from Santa Cruz, California, by Dr. 

 Sinclair (Busk '54), and froiu Queen Charlotte Islands by Hincks 

 ('84). Our collection shows it obtained at various localities of 

 the more northern coast of California, and also from Alaska. 



82. Cellepora costazi Audouin. 



PI. 24, fig. 89. 



Cellepora Costazii Aiidonin, 1826. 



Cellepora Costazii, Hincks, 1880, p. 411, pi. 55, fig. 11-14. 



Zoarium incrusting stems, growing in many superposed lay- 

 ers. Zooecia decumbent, in earliest stages, smooth ; in later stages, 

 erect, disposed irregularly and crow^ded together one on top of 

 another, wall perforated by large pores (pi. 24, fig. 89) ; orifice 

 suborbicular, wath a sinus on the lower margin ; becoming deeply 

 sunk secondarily by the growth of the peristome bearing an erect 

 process on each side of the orifice with a small avicnlarium on its 

 sunnnit ; sometimes a third process on the upper margin of those 

 zofficia that do not bear an ovicell ; many zooecia with no process 

 whatsoever. Scattered irregularly over the colony are large 

 raised spatulotc avicnlaria, sp. av., formed in place of a zocpcium, 

 mandible rounded and directed in any direction. Ooecia decum- 

 bent, rounded, smooth, much broader than high, with an area in 

 front pierced by large openings or pores. 



This species differs from the typical G. Costazii mainly in the 

 perforations of its walls. This can not be said to be due to the 

 calcification that comes with age since it appears in the youngest 

 z()(i^cia. In othei' respects it conforms to the type and until com- 

 parison can be made it is retained here. Obtained at various 

 points on the southern shores mainly. It is much less abundant 

 than C. incrassata. 



