54 BULLETIN 90, UNITED STATES NATIONAL MUSEUM. 



formed of diagonal bars. The frontal is a tremocyst with tubules. 

 Twenty tentacles. 



Genotype. — Porella {Millepora) cervkornis Pallas, 17GG. 



Range. — Lutecian-Eecent. 



This genus differs from BmUtina only in the calcification; the 

 tremocyst replaces the pleurocyst. There are, however, some other 

 secondary differences. The mandible of the avicularium is semi- 

 circular; it is generally (but not universally) triangular in Smlttina. 



This is a prolific genus in the Early Tertiary of North America, 

 15 new species being known, represented in most cases by abundant 

 specimens. 



Genus UMBONULA Hincks, 1880. 



1S80. Umhonnla Hinck, British Marine Polyzoa, p. 316. 



There is neither lyrule nor cardelles. The apertura is suborbi- 

 cular. The ovicell is hyperstomial and opens largely above the aper- 

 tura. The frontal is a pleurocyst with costules surrounded by areo- 

 lae. A prominent umbo immediately below the mouth, supporting 

 an avicularium. 



Genotype. — Umhonula (Cellepora) verrvcosa Esper, 1791. 



Range. — Lutecian-Eecent. Eepresented by two species in the 

 Vicksburgian of Alabama. 



Genus PHOCEANA Jullien, 1903. 



1903. riioceana Jullien, Bryozoaires provenaut des Campagnes de VHiron- 

 dcUc, p. 107. 



The apertura is semicircular with poster slightly concave; it is 

 deprived of cardelles and bears a pseudolyrule formed by the eleva- 

 tion of the peristomial wall. The operculum bears a chitinous mural 

 rim incomplete at the level of the convexity of the upper border and 

 little removed from the lateral borders. 



Genotype. — Phoceana columnaris Jullien, 1903. 



Range. — Jacksonian-Eecent. 



HIPPADENELLA, new genus. 



{Aden., gland.) 



The frontal is a pleurocyst surrounded by areola?. The apertura 

 bears two cardelles. The mandibles have a lucida in the middle. The 

 avicularian chamber shows a double glandlike body and the pro- 

 toj^lasmic mass. 



Genotype.— Hip padenella (Flustra) margaritifera Quoy and Gay- 

 mard, 1833. Eecent. 



It seems to us that it would be better to classify this genus in the 

 Hippoporinae, although all the authors are agreed in considering 



