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154 BULLETIN 125, UNITED STATES NATIONAL MUSEUM. 
Genus PHIDOLOPORA Gabb and Horn, 1862. 
1862. Phidolopora Gabb and Horn, Monograph Polyzoa of the Secondary and Tertiary Formations 
of North America, Journal Academy National Science Philadelphia, ser. 2, vol. 5, p. 138. 
The frontal of the ovicell is not fissured. The aperture is semilunar, with a 
concave proximal border. The peristomice bears a rimule spiramen. The frontal 
is an olocyst. No labial avicularium. 
Genotype.—Retepora labiata Gabb and Horn, 1862. Pleistocene, Recent. 
Affinities. —The apertura is identical with that of the genus Retepora Imperato, 
1859, as Waters has limited it in 1913. The genus Phidolopora Gabb and Horn, 
1862, differs from it in the absence of a fissure on the ovicell, in the replacement of 
the spiramen by a rimule of the peristomice, and in the absence of the labial avicu¬ 
larium. Moreover, the frontal is an olocyst, a character which does not exist 
notably in the group of Sertella Jullien, 1903. The definition of Gabb and Horn 
1862, has no significance; it is even little comprehensible: "It differs from Re¬ 
tepora by the scattered special pores over the surface of the colony.” Retepora 
pacijxca Robertson, 1908, belongs absolutely to the same group and shows the 
generic characteristics clearly. 
PHIDOLOPORA PACIFICA Robertson, 1908. 
Plate 39, figs. 1-7. 
1908. Retepora pacifica Robertson, The incrusting cheilostomatous Brvozoa of the west coast of 
North America, University of California Publications, Zoology, vol. 4, p. 310, pi. 24, figs. 
81-84. 
Measurements— Peristomice: Ipe = 0.14-0.16 mm. 
r , . \Lz = 0.40-0.60 mm. „ , \Lf =1.75 mm. 
Zooecia 7 „ on benestrae _ __ 
l 42 = 0.30 mm. [ If =0:50 mm. 
Affinities. —This species differs from Phidolopora labiata Gabb and Horn, 1862, 
in its larger peristomice always wider than 0.14 mm.; thus the apertures appear 
closer together. The small tongue on the ovicell mentioned by Miss Robertson is 
too fragile to be preserved on the fossils. The zooecia deprived of the large frontal 
avicularium bear some small scattered pores. In tangential section the vibices 
appear clearly. They are therefore formed by a very dense calcification in the 
entire thickness. of the zoarial dorsal. Sometimes the dorsal bears radicular pores. 
In transverse sections the lacunae appear very irregularly arranged. 
Occurrence. —Pleistocene: Santa Monica (rare), and Dead Mans Island, off San 
Pedro (rare), California. 
Habitat. —Coast of California. 
Plesiotypes.— Cat. No. 68662, U. S. N. M. 
PHIDOLOPORA LABIATA Gabb and Horn, 1862. 
Plate 39, figs. 13-17. 
1862. Phidolopora labiata Gabb and Horn, Monograph Polyzoa of the Secondary and Tertiary 
formations of North America, Journal Academy Natural Sciences, Philadelphia, ser. 2, 
vol. 5, p. 138, pi. 19, fig. 21. 
Description. —The zoarium is reticulated; the fenestrae are narrow and elon¬ 
gated. The zooecia are distinct, margined by a salient thread, elongate, fusiform; 
the frontal is slightly convex and smooth. The apertura (visible only in the inte- 
