164 BULLETIN 125, UNITED STATES NATIONAL MUSEUM. 



Genus PHIDOLOPORA Gabb and Horn, 1862. 



1862. Phidohpora Gabb and Horn, Monograph Polyzoa of the Secondary and Tertiary Formations 

 of North America, Journal Academy National Science Philadelphia, Ber. 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 runule 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 PMdolopora 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 

 pacifica 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 incruating cheilostomatous Bryozoa of the west coast of 

 North America, University of California Publications, Zoology, vol. 4, p. 310, pi. 24, figs 

 81-84. 



Measurements. — Peristomice: Zpe = 0.14-0.16 mm. 



rj . [is = 0.40-0.60 mm. _ (i/'=1.75mm. 



Zooecia , . „. Fenestrae f!. ^ '^ 



liz = 0.30mm. |Z/=0.50mm. 



Affinities.— This species differs from PMdolopora 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. 



Occwrrence.— 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. 



PmOOLOPORA LABIATA Gabb and Horn. 1862. 



Plate 39, figs. 13-17. 

 1862. PMdolopora labiata Gabb and Horn, Monograph Polyzoa of the Secondar^• and Tertiary 

 formations of North America, Journal Academy Natural Sciences, Philadelphia ser 2 

 vol. 5, p. 13S-, pi. 19, fig. 21. F , • , 



Description.— The zoarium is reticulated; the fenestrae are narrow and elon- 

 gated. The zooecia are distinct, margined bv a salient thread, elongate, fusiform- 

 the frontal is slightly convex and smooth. The apertura (visible only in the inte- 



