NO. 1 OSBURN : EASTERN PACIFIC BRYOZOA CHEILOSTOMATA 73 



Gopidozoum planum (Hincks), 1880 



Membranipora plana Hincks, 1880a:81. 

 Gopidozoum planum, Hastings, 1930:713. 



"Zooecia large, oval, distinct, surrounded by a narrow border, which 

 is rounded and finely crenate, sometimes slightly produced below the 

 aperture and pointed ; front wall wholly membranous, very much on a 

 level with the margin of the cell, so as to give a flattened appearance to 

 the surface of the zoarium. Avicularia scattered, placed in somewhat 

 lozenge-shaped intercellular spaces; beak elongate, straight, occupying 

 the center of the area, traversed by a narrow groove which expands 

 toward the lower extremity; mandible with an enlarged base, above it 

 setiform, slightly curved at the top. Ooecium rounded, rather large, 

 frosted." (Hincks 1880a :81). 



The species was described from Australia and has since been recorded 

 from the Mediterranean (Canu and Bassler 1928:32); from Japan 

 (Membranipora vibraculoides Okada, 1923:223), and Hastings has 

 listed it from Coiba, Panama; Gorgonia, Colombia; the Galapagos Is- 

 lands, and also mentions specimens from California in the British Mu- 

 seum. In all the numerous specimens I have examined from all along the 

 coast from California to the Galapagos Islands there are none that I can 

 positively separate from tenuirostre except on the basis of the lack of 

 spines. I have found occasional specimens with thinner walls, but these 

 were not larger than tenuirostre. This raises the question whether only 

 those with heavy spines, as shown by Hincks (1880, plate 9, fig. 3) and 

 Marcus (1937, text fig. 7) should be included in tenuirostre and those 

 without spines under planum, regardless of the width of the cryptocyst. 

 On this basis all of the Pacific coast specimens belong under planum. 



^j Gopidozoum protectum (Hincks), 1884 

 Plate 7, fig. 5 



Membranipora protectum Hincks, 1884:10. 

 Membranipora protectum, O'Donoghue, 1923 :25. 

 Amphiblestrum protectum, O'Donoghue, 1926:38. 



Zoarium encrusting. Zooecia very distinct, moderate in size, 0.40 to 

 0.50 mm long by 0.25 to 0.30 mm wide. Gymnocyst and cryptocyst both 

 small and the opesia occupies nearly all of the frontal area. The mural 

 rim is thin and high, the descending cryptocyst narrow, without hori- 

 zontal shelf, granulated. Spines: one erect, simple or slightly bifid, at 

 each distal corner; one on each side of the operculum, also erect and 



