418 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



Genus HIPPOPORIDRA Canu and Bassler, 1927 



The ovicell is hyperstomial and bears a frontal area. The zooecia 

 are accumulated; the frontal is surrounded by areolar pores and often 

 bears small avicularia. The aperture is formed of an anter and a 

 poster separated by two cardelles. The large interzooecial avicularia 

 are acuminated. 



Genotype. — Hippoporidra (CeUepora) edax Busk, 1859. 



Range. — Miocene — Recent . 



The known species of this genus are as follows: 



Hippoporidra {CeUepora) edax Busk, 1859 Recent, fossil. 



Hippoporidra (Lepralia) calcarea Smitt, 1873 Recent, fossil. 



Hippoporidra {Lepralia) maculata Ulrich and Bassler, 1904 Miocene. 



Hippoporidra [Lepralia) parvula Canu and Bassler, 1923 Miocene. 



Fig. 163. — Genus Hippoporidra, new genus 



A, B. Hippoporidra edax Busk, 1859. A. Zoarium, natural size. B. Zooecia 

 X40. (A, B. After Hincks, 1880.) C-H. Hippoporidra calcarea Smitt, 1873. C, 

 D. Subcylindrical colonies, natural size. E. Ordinary zooecia, X40. F. Surface 

 with ovicelled zooecia and avicularia, X40. (C-F. After Smitt, 1873.) G, H, 

 Two opercula, one (G) of ordinary zooecium and another (H) of an ovicelled 

 one, X85. 



Genus HIPPOTREMA Canu and Bassler, 1927 



The ovicell is hyperstomial and is not closed by the operculum. 

 The zooecia are piled upon each other in disorder; their frontal is 

 perforated by tremopores. The aperture is formed by a large 

 orbicular anter and by a short poster, separated by two cardelles. 

 The operculum does not have lateral linear attachments. 



Genotype. — Hippotrema (Lepralia) javthina Smitt, 1873. 



lianrje. — Recent. 



