10 BULLETIN 96, UNITED STATES NATIONAL MUSEUM. 



nomenclature with fossils alone we must be content to utilize the 

 works of our predecessors. We have studied especially the ovicells 

 and their relations to the opercular valve, for these are the organs 

 in closest relation to the larval system. In the following table are 

 listed the genera of M emhraniporae with the possible family refer- 

 ence of some of them. 



SECTION I.— NO VIC ELL. 



ConojyeuTn Norman, 1903. Cenomanian-Eecent. 

 M emhraniporlna Levinsen, 1909. 

 OdontioneUa^ new genus. Lutecian-Recent. 

 Adenifera^ new genus. Jacksonian-Recent. 

 Trochopora D'Orbigny. Lutecian-Helvetian. 

 Otionella, new genus. Campanian-Jacksonian. 



SECTION H. OVICELL ENDOZOCECIAL. 



Vibracellina, new genus. Claibornian Lunulariidae. 



Hincksina Norman, 1903. Jacksonian-Eecent.Flustridae (Norman). 



Ogivalina, new genus. Jacksonian Onychocellidae. 



Memhrcndoecimji, new genus. Eocene-Recent Farmicinariidae. 



SECTION III. OVICELL HYPERSTOMIAL, CLOSED BY THE OPERCULAR 



VALVE. 



Periporosella, new genus. Jacksonian. 

 Ellisina Norman, 1913. Senonian-Recent. 

 Grammiella Canu, 1916. Santonian-Recent. 

 Membranipmidra, new genus. Jacksonian- Vicksburgian. 

 Tremopora Ortman, 1890. Helvetian-Recent. 

 Larnacius Norman, 1903. Recent. 



SECTION IV. OVICELL HYPERSTOMIAL, NOT CLOSED BY THE OPERCULAR 



VALVE. 



Alderiiia Norman, 1903. Senonian-Recent. 



Callopora Gray, 1818. Santonian-Recent. 



ATnjyhiblestrmn Gray, 1848. Senonian-Recent. 



Ramphonotus Norman, 1891. Senonian-Recent. 



Tegella Levinsen, 1909. Santonian-Recent. 



StaonenoceUa^ new genus. Senonian-Vicksburgian Bicellariidae. 



SECTION I. MEMBRANIPORAE WITHOUT OVICELL. 



Genus CONOPEUM Norman, 1903. 



1903. Conopeiim, Norman, Natural History of East Finmnrk, Annals Maga- 

 zine Natural History (7), vol. 11, p. 580 (18-18. Gray, List British 

 Animals British Museum, Centroniae, pp. 108, 146). 



No ovicell, no dietellae, no avicularia. The margins of the mural 

 rim are wholly granulated. A distal, multiporous septula ; 2 or 3 



