NO. 2 OSBURN: eastern pacific BRYOZOA — CHEILOSTOMATA 387 



The ovicell is large, about 0.26 mm wide, rounded, perforated like 

 the frontal, striated lightly and radially in the young stage; a visor-like 

 projection usually extends above the orifice. 



In the absence of ovicells this species may be confused with M. 

 pontifex, new species, as both have hastate avicularian mandibles, but 

 in the latter the avicularia are single and quite proximal to the ascopore. 

 When an ovicell is present the peristome at the sides of the aperture is 

 not raised, while in pontifex the lateral peristomial lappets are high and 

 meet above the aperture. 



It is distributed around the world in warmer waters, and Hastings 

 has recorded it from Coiba, Panama, and Gorgona, Colombia. Hastings 

 also places M. calif ornica (Busk) under the synonomy of coronata, but 

 this is incorrect as the mandible is never hastate and the rostrum is 

 pointed ; also it is a larger and coarser species than coronata. 



Hancock Station 650-37, E of San Francisco Island, Gulf of Cali- 

 fornia, 47 fms, several colonies. 



Genus FENESTRULINA Jullien, 1888 



This genus differs from Microporella by the stellate character of 

 the tremopores, by the more proximal position of the ascopore so that 

 there are one or two rows of tremopores between it and the aperture, 

 and by the absence of avicularia. Genotype, Cellepora malusii Audouin, 

 1826. 



Fenestrulina malusi (Audouin), 1926 

 Plate 45, fig. 3 



Microporella malusii, Hincks, 1884:16. 

 Microporella malusi, Robertson, 1908:282. 

 Microporella malusii, O'Donoghue, 1923:32. 

 Fenestrulina malusii, O'Donoghue, 1926:63. 

 Fenestrulina malusi, Canu and Bassler, 1923:115. 

 Fenestrulina malusi, Osburn, 1940 :433. 



The zoarium forms white, flat encrustations on shells and stones. 

 The zooecia are moderately large, irregularly hexagonal, sometimes as 

 broad as long, very distinct with deep separating grooves and the front 

 considerably inflated, the surface smooth ; the stellate tremopores numer- 

 ous. There is much variation in size of the zooecia, which average about 

 0.60 mm long by 0.50 mm wide. The aperture is semicircular, with 



