NO. 2 OSBURN: eastern pacific BRYOZOA CHEILOSTOMATA 353 



is slightly longer than wide, about 0.10 by 0.08 mm, rounded distally, 

 nearly straight on the sides and broadly arcuate on the proximal border 

 (often nearly straight), the small cardelles set far back. The operculum 

 has the form of the aperture, well chitinized, with a narrow sinuate 

 sclerite running forward from the hinge inside from the border. The 

 primary peristome is low and smooth and bears 6 slender spines which 

 soon disappear; the frontal wall usually obscures the peristome. A 

 minute pointed oral avicularium is sometimes present beneath the 

 overhanging umbo; small frontal avicularia with a triangular mandible 

 are scattered over the frontal area proximal to the aperture. 



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

 broader than long and heavily calcified like the frontal; the orifice is 

 comparatively wide and its upper edge is directed downward into a broad 

 rounded labiate projection. 



Described from the Tortugas Islands, Florida, and later reported 

 by Osburn from Porto Rico and the southern Caribbean Sea. 



Hancock Stations: 299, San Jose del Cabo, at the tip of the Lower 

 California peninsula; 129-34, Braithwaite Bay, Socorro Island, west 

 of Mexico; 116-33, Cocos Bay, 253-34, Port Culebra, and 328, Chatham 

 Bay, Cocos Island, Costa Rica; 210-34, Santa Elena Bay, Ecuador; 

 173-34, South Seymour Island, Galapagos. 



Aimulosia palliolata (Canu and Bassler), 1928 

 Plate42, figs. 9-11 



Lepr alia palliolata Canu and Bassler, 1928:109. 



Zoaria small, white, encrusting shell fragments. The zooecia are 

 distinct with deep separating grooves, ovate to elongate-hexagonal, 0.40 

 to 0.50 mm long by 0.25 to 0.35 mm wide. The frontal is a thick 

 pleurocyst with one row of areolar pores, the surface smooth or with 

 low irregularities: enclosing sides of the aperture and the suboral 

 avicularium at a little distance is a high fold which is probably homol- 

 ogous with the umbonal process of other species of the genus. The 

 aperture is widest proximal to the cardelles, 0.10 mm long by 0.08 mm 

 wide, the poster shallow and its border slightly concave. The operculum 

 is well chitinized, a narrow sclerite extends straight across it between 

 the cardelles and a very narrow sclerite close to the border bears the 

 muscle attachments. The primary peristome is low and thin and bears 

 4 to 6 comparatively strong oral spines ; the secondary peristome, formed 

 by the frontal pleurocyst, rises into a high flaring wall which surrounds 



