NO. 2 osburn: eastern pacific bryozoa — cheilostomata 291 



Genus COLEOPORA Canu and Bassler, 1927 



"The zooecia are exceptionally large; the frontal is a tremocyst with 

 small pores. The ovicell is hyperstomial and never closed by the oper- 

 culum. The apertura is buried at the bottom of a long tubular peristomie 

 with structure different from that of the frontal. The operculum bears 

 two long lateral attachments" (Canu and Bassler, 1929:267). Geno- 

 type, Coleopora verrucosa Canu and Bassler, 1927:6. 



Coleopora gigantea (Canu and Bassler), 1923 

 Plate 32, figs. 9-10 



Cyclicopora{ ?) gigantea Canu and Bassler, 1923:139. 



Zoarium encrusting on rough or nodular surfaces, light yellowish in 

 color. The specific name, gigantea, was well chosen for this is one of the 

 very largest of all ascophoran species. The measurements vary greatly, 

 usually the length is somewhere between 1.00 and 1.50 mm but occasional 

 zooecia as short as 0.90 and as long as 2.00 mm have been noted. The 

 width is usually between 0.80 and 1.00 mm. The highly convex front 

 also adds to the bulk of the zooecium. The individuals are unusually 

 distinct. The frontal is a somewhat reticulated, thick tremocyst with 

 small pores and this is continued forward along the sides of the aperture. 

 The primary peristome is low and thin, but the secondary peristome is 

 a high, vertical, smooth-walled tube which often flares slightly at the 

 border, of equal height on all sides. The aperture is noticeably elongate, 

 0.35 to 0.40 mm long by 0.24 to 0.30 mm wide, rounded distally, nearly 

 straight on the sides and broadly arcuate on the proximal border. The 

 operculum is well chitinized, with a strong bordering sclerite distally; 

 inward from the lateral border a heavy sclerite runs forward from the 

 point of attachment to the prominent muscle scars and then more lightly 

 to near the tip of the operculum ; the latter sclerite is enlarged at the 

 point of attachment, but cardelles are diminutive or usually wanting. 

 No spines, no avicularia. 



The ovicell is correspondingly large, about 0.60 mm wide by 0.50 mm 

 long, very prominent, globular, somewhat roughened, a semilunate band 

 of different texture on each side, these often broadly coalesced above the 

 orifice ; not closed by the operculum. 



Canu and Bassler described the species from the Pleistocene of Santa 

 Monica, California. Our recent specimens appear to agree with the 

 description in every detail except that the aperture is slightly more 

 elongate. 



