344 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



Genus HIPPOPORINA Neviani, 1895 



The aperture Is unusually elongate, due to the form and size of the 

 area proximal to the large cardelles > the operculum has the form of the 

 aperture, constricted by the cardelles, is well chitinized and bears a 

 bordering sclerite to which the opercular muscles are attached ; a ves- 

 tibular arch is present; the frontal is a thick olocyst which bears a few 

 areolar pores ; avicularia are usually present and oral spines may occur. 

 The ovicell is hyperstomial and is closed by a special membrane. 



Key TO THE Species of Hippoporina 



1. Zooecia large, more than 1 row of areolar pores, poster a broad 



deep arc ampla 



Zooecia of moderate size, few areolar pores in 1 row .... 2 



2. Poster a broad deep arc, conical tubercles at the sides of the 



aperture tuberculata 



Poster deep and narrow 3 



3. Poster rounded, frontal surface smooth or slightly 



granular porcellana 



Poster semicircular, front roughened, cardelles usually 



bifid contracta 



Hippoporina porcellana (Busk), 1860 

 Plate 41, figs. 1-3 



Lepralia porcellana Busk, 1860 :284. 

 Lepralia cleidostoma Smitt, 1873 :62. 

 Lepralia cleidostoma. Waters, 1899 : 10. 

 Lepralia porcellana, Norman, 1909:305. 

 Hippoporina cleidostoma, Canu and Bassler, 1928 :104. 

 Hippoporina porcellana, Hastings, 1930:721. 

 Hippoporina cleidostoma, Canu and Bassler, 1930:18. 

 Hippoporina porcellana, Marcus, 1937 :96. 

 Hippoporina porcellana, Osburn, 1940 :428, 



The zoarium is encrusting, usually on shells, white and glistening. 

 The younger zooecia are distinct, rhombic in form and a little inflated, 

 but with age the thick crust becomes nearly flat and obliterates the out- 

 lines. The frontal is a thick olocyst with only a few areolar pores, smooth 

 but with complete calcification, it is decorated with low, rounded granules. 

 The primary aperture is round to the long cardelles, which are directed 



