310 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



Affinities. — The micrometric measurements are very variable. The 

 interareolar costules are often much attenuated and little visible. 



This species differs from Gemellipora auriculata Maples tone, 1901, 

 in its granular frontal and from Gemellipora elegantissima Mac- 

 Gillivray, 1895 in the presence of a large oral avicularium. 



Biology. — Almost all of our specimens were dead and we do not 

 know the time of reproduction and of fixation. This is a deep 

 water species; it accommodates itself to the bathymetric conditions of 

 the north of Sulu Sea while those of the Sulu Archipelago where the 

 water is warm, shallow, and very calm, appear rather unfavorable to it. 

 Occurrence. — 



D. 5145. Jolo Light, Jolo; 6° 04' 30" N.j 120° 59' 30" E.; 23 



fathoms; co. S., Sh. 

 D. 5179. Romblon Light, Romblon; 12° 38' 15" N.; 122° 12' 



30" E.; 37 fathoms; hard S.; 24.2° C. 

 D. 5192. Jilantaguan Island, off northern Cebu Island; 11° 09' 



15" N.; 123° 50' E.; 32 fathoms; green sand. 

 D. 5217. Anima Sola Island, between Burias and Luzon; 13° 20' 

 N.; 123° 14' 15" E.; 105 fathoms; crs. gy. S. 

 (common). 

 D. 5219. Mompog Island, between Marinduque and Luzon; 13° 

 21' N.; 122° 18' 45" E.; 530 fathoms; gn. M.; 10.4°. 

 D. 5579. Sibutu Island, Darvel Bay, Borneo; 4° 54' N.j 119° 09' 

 52" E.; 175 fathoms; fine, S. co.; 13° C. 

 Cotypes.— Cut. Nos. 8062, 8063, U.S.N.M. 



Genus GEMELLIPORIDRA Canu and Bassler, 1927 



The ovicell is hyperstomial and is always closed by the operculum. 

 The frontal and the ovicell are covered by tremopores. The aperture 

 bears two small lateral indentations separating a very large sub- 

 orbicular anter from a very small concave poster. The operculum 

 bears two lateral marks corresponding to oral indentations and two 

 linear muscular attachments. There are two oral avicularia irregu- 

 larly arranged on each side of the aperture. The complete colonies 

 are multilamellar and the zooecia are then poorly oriented. 



Genotype. — Gemelliporidra typica Canu and Bassler, 1927. Recent. 



Range. — Pleistocene. Recent. 



Genus GEMELLIPORA Smitt, 1872 



GEMELLIPORA PERISTOMARIA, new species 



Plate 34, fig. 1 



Description. — The zoarium encrusts shells. The zooecia are dis- 

 tinct, separated by a deep furrow, somewhat elongated, swollen, 

 bottle-shaped; the frontal is quite convex, finely granular and orna- 



