320 



BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



Occurrence. — D. 5162. Tinagta Island, Tawi Tawi Group; 5° 10' 

 N.; 119° 47' 30" E.; 230 fathoms; S. brk., Sh. crs.; 11.6° C. 

 Holotype— -Cat. No. 8083, U.S.N.M. 



HIPPOPORINA FALLAX, new species 



Plate 37, figs. 4, 5 



Description. — The zoarium encrusts Orbitoides, nullipores, and 

 small fragments of shells; it is sometimes multilamellar. The zooecia 

 are distinct, separated by a furrow, somewhat elongated, deformed by 

 a very large lateral avicularium; the frontal is expanded, convex, 



Fig. 132. — Genus Hippoporina Neviani, 1895 



A. Hippoporina Integra Neviani, 1895. Ovicelled and ordinary zooecia, X25. 

 (After Neviani, 1895.) 



B-E. Hippoporina cleidostoma Smitt, 1873. B. View of zooecia. (After Smitt, 

 1873.) C, D, E. Various opercula, X85. 



F-H. Hippoporina porcellana Busk, 1860. F. G. Opercula from same colony, 

 X85 (after Waters, 1898). H. Operculum. (After Norman, 1909.) 



I. Hippoporina fallax Canu and Bassler. Operculum, X85. 



J. Hippoporina planulata Canu and Bassler. Operculum, X85. 



K. Hippoporina eliminata Waters, 1887. Operculum, X85. (After Waters.) 



very finely granular. The apertura is elongated, bordered, the 

 anter is quite large and pyriform. The poster is small and enlarged 

 in its proximal portion. The ovicell is smooth, convex, not closed 

 by the operculum, globulose. 

 Measurements. — 



Apertura 



ha 



=0-14 mm. Zooed (Zz =0.40 mm. 



[Za=0.12mm. \lz =0.30-0.40 mm. 



Affinities. — At the first examination and in the presence of a large 

 lateral avicularium this species has the aspect of a Gemellipora. 

 This appearance is deceiving as close examination of the aperture 



