NORTH AMERICAN LATER TERTIARY AND QUATERN.ARY BRVOZOA. 179 



avicularium hides the apertura. The apertura is semilunar. The ovicell is globular, 

 transverse, smooth; it is widely open in front of the umbo and never closed by the 

 operculum. 



[Z2 = 0.50-0.60 mm. 



Measurements. — -Zooecia , „ „, „ ,„ 



[Iz =0.2o-0.40 mm. 



Affinities. — The interareolar costules are easily attenuated by fossilization and 

 are visible only on the good specimens. The anccstrular zooecia are smaller and 

 raised. 



In its exterior aspect this species is close to Cellepora pumicosa Linnaeus, 176S; 

 it differs from it in the presence of the interareolar costules and in a different form 

 of the apertura. 



Occurrence. — Pleistocene: Santa Barbara (rare) and Santa Monica (Temochal 

 Canyon), California (very rare). 



Cotypes.— Cat. No. 68707, U.S.N.M. 



HOLOPORELLA TURRITA Smitt, 1873. 



Plate 4G, fig. 1. 

 1873. Lepralia turrita Smitt, Floridan Bryozoa, pt. 2, Kongl. Svenska Vetenskaps-Akademiens 



Handlingar, vol. 11, no. 4, p. 65. 

 1914. Holoporella turrita Osburx, The Bryozoa of the Tortugas Islands, Florida, Publication 



Carnegie Institution of Washington, no. 182, p. 217 (bibUography). 



Our specimen incrusts a coral. The apertura bears two small cardelles, placed 

 in the lower third. 



Occurrence. — Pleistocene: Mount Hope, Panama Canal Zone (very rare). 

 Habitat. — Waters off Florida (14-71 meters). 

 Plesiotype.—Qtii. No. 68708, U.S.N.M. 



HOLOPORELLA AVICULIFER.4. new species. 



Plate 46, fig. 2. 



Description. — The zoarium incrusts corals, forming very thick masses. The 



zooecia are somewhat erect, convex, and formed of a tremocj'st w,ith scattered, 



spaced pores; the frontal bears some interareolar costules. The apertura is formed 



of a large anter and of a concave poster and arranged at the base of a short peristomie. 



There is a small avicularium in the peristomie. On the frontal some areolar pores 



are transformed into sntall orbicular avicularia. 



,, , . , |/(a = 0.1S mm. 



Measurements. — Apertura U ^ .^„ 



'^ |Za = 0.20 mm. — 



Affi-nities. — This species presents somewhat the aspect of Discopora pertusa 

 Smitt, 1872. It differs from it in the presence of the small disseminated avicularia 

 and in the absence of oral mucro. 



Occurrence. — Pleistocene: Mount Hope, Panama Canal Zone (rare). 



Holotype.—C&t. No. 68709, U.S.N.M. 



HOLOPORELLA MUCRONATA. new species. 

 Plate 46, tig. 7. 

 Description. — The zoarium incrusts sponges. The zooecia are little erect, sur- 

 rounded by a line of large, spaced, areolar pores; the little salient, areolar costules 

 meet at an enormous, vs-ide, oral, very salient mucro. Two very small cardelles 

 separate the anter from the concave poster. Some areolar pores are transformed 

 into small orbicular or triangular avicularia. 



