BRYOZOA OF THE PHILIPPINE REGION 115 



Genus HIANTOPORA MacGillivray, 1887 



1887. Hianlopora MacGillivray, Catalogue Marine Polyzoa of Victoria, Trans. 



Royal Society Victoria, vol. 23, p. 208. 

 1902. Membrostega Levinsen. See Canu and Bassler, North American Early 



Tertiary Bryozoa, p. 174, fig. 41 C. 



The ovicell is deeply buried in the distal zooecium and never closed 

 by the operculum. The frontal membrane is covered by branched 

 projections; these are hollow and originate from the avicularia. The 

 ectocyst is below the perforated frontal. 6 



Genotype. — Hianlopora jer ox MacGillivray, 1868. 



Range. — Miocene to Recent. 



The known species of this genus are as follows: 



Hianlopora ferox MacGillivray, 1868 Recent. 



Hianlopora spathulala, new species Recent. 



Hianlopora bidenticulala, new species Recent. 



Hianlopora laticella, new species Recent. 



Hianlopora halli MacGillivray, 1895 Miocene. 



Hianlopora liversidgei MacGillivray, 1895 Miocene. 



Jullien in 1903 applied the name Membrostega to this genus and 

 erroneously attributed the formation of the frontal to the fusion of 

 the branches of two large bifurcated oral spines. 



HIANTOPORA BIDENTICULATA, new speciea 



Plate 11, figs. 9-11 



Description. — The zoarium encrusts nullipores and shells. The 

 entire zooecia are little distinct; they are somewhat elongated and 

 elliptical; the mural rim is thin, regular, with two distal bifurcated 

 spines and two elliptical, oral avicularia; the opesium (invisible) is 

 large and of the same form as the zooecia. The frontal is perforated 

 with 5 or 6 large round pores. The orifice, placed above the opercular 

 valve is elliptical, transverse, with a proximal salient lip ornamented 

 with two large spicules. The ovicell is immersed in the distal zooe- 

 cium, little apparent, convex. 



Variations. — The adventitious frontal formed by the ramifications 

 and union of the spines developed at the base of the two avicularia, 

 is quite variable. The two avicularia themselves have their orifice 

 sometimes perpendicular and sometimes parallel to the zooecial plane; 

 in the first case they are very salient. 



The visible orifice is neither an opesium nor a regular aperture; it 

 serves, however, for the passage of the tentacles. The use of the 

 bidenticulato mucro is difficult to understand. 



Affinities. — The structure is absolutely analogous with that of the 

 genotype Iliantopora ferox MacGillivray, 1868, but the present 

 species differs in the occurrence of two avicularia and in the bidenticu- 

 latcd mucro on the frontal. 



• We are naming this calcareous frontal above tlie chltlnous ectocyst, tlio pcricyst. 



