NO. 2 OSBURN : EASTERN PACIFIC BRYOZOA — CHEILOSTOMATA 441 



Family Adeonidae Jullien, 1903 



The frontal is a thick pleurocyst ; the areolae are unique in that they 

 do not open directly through the frontal wall but proceed downward in 

 the lateral wall to communicate with the septulae. In some genera there 

 is an ascopore which may be near the center of the front wall, but in 

 other genera the compensatrix opens in the sinus of the aperture. The 

 fertile zooecia are gonozooecia which are usually larger and provided 

 with a larger aperture. Both frontal and interzooecial avicularia may 

 be present. 



Genus ADEONA Lamouroux, 1812 



Zoarium encrusting. Frontal wall a thick pleurocyst, with an asco- 

 pore in the center ; tubular areolar pores ; primary aperture at the bottom 

 of a peristomial tube. Ovicells endozooecial on gonozooecia which are 

 usually larger than ordinary zooecia and without a peristome. Geno- 

 type, Adeona grisea Lamouroux, 1816. 



Adeona violacea (Johnston), 1847 

 Plate 58, figs. 6-7 



Lepralia violacea Johnston, 1849:325. 

 Porina violacea, Smitt, 1873 :30. 

 Microporella violacea, Hincks, 1880:216. 

 Adeona violacea, Oshurn, 1914:199; 1940:445. 

 Adeona plagiopora, Canu and Bassler, 1928:126. 

 Adeona violacea, Hastings, 1930:728. 



Zoarium encrusting, often forming rounded nodules, ranging in color 

 from lavender to intense purplish-black. The zooecia are moderate in 

 size, 0.40 to 0.55 mm long, 0.25 to 0.30 mm wide, the frontal somewhat 

 ventricose, the pleurocyst thick and roughened with a row of conspicuous 

 areolar pores. At or near the center is an ascopore which, with the thick- 

 ening of the front, lies at the bottom of a rounded indentation. An 

 avicularium with a pointed mandible is situated between the ascopore 

 and the aperture and directed distally in the midline (directed more or 

 less laterally in the variety plagiopora). The primary aperture is small, 

 transversely short-elliptical, averaging about 0.12 mm wide by 0.09 mm 

 long ; there is a short-tubular peristome. No spines. 



The gonozooecia are slightly larger than the infertile zooecia and 

 the aperture measures about 0.15 mm wide. 



