EAELY TERTIARY CHEILOSTOME BEYOZOA. 55 



the genotype as belonging to the genus Porella; we can not maintain 

 it there, the frontal being a pleurocyst and the apertura bearing 

 cardelles. 



Family RETEPORIDAE Smitt, 1867. 



The ovicell is hyperstomial, much immersed in the distal zoojcium ; 

 it is largely open into the peristomie. The zoarium is generally 

 reticulate ; the dorsal face presents some projections or vibices with- 

 out connection with zooecia and contains interiorly some keno- 

 zoa?cia (lacimae of Waters) more or less numerous and elongated. 

 The reteporidan pore placed in front of the apertura is according 

 to its situation an ascopore or a spiramen; 11 to 16 tentacles. 



Genus RETEPORA Imperato, 1859. 



1859. Retepora Imperato, Dell' historia naturale, book 28. 



" This gi'oup has a fissure in the ovicell. The proximal edge of the 

 operculum is nearly straight, and very similar throughout this 

 group; labial avicularia occur in some but not in all. The oral 

 glands are very well developed" (Waters). The reteporidan pore 

 is a spiramen. 



Genotype. — Retepora cellulosa Linnseus-Smitt, 1867. 



Range, — Jacksonian-Recent. 



HIPPELLOZOON, new genus. 



{Hippos^ horse, referring to the horseshoe shape of the apertura.) 



The ovicell is widely open. There is neither labial avicularium 

 nor reteporidan pore. The operculum is contracted in the middle, 

 having long bands at the sides for the muscular attachments; the 

 proximal edge is not straight. The apertura has two cardelles. 



Genotype. — Hippellozoon {Retepora) novezelandiae Waters, 1894. 

 Recent. 



SCHIZELLOZOON, new genus. 



(Schizos, slit). 



The ovicell is widely open and provided with a semicircular slit. 

 It has neither labial avicularium nor reteporidan pore. The oper- 

 culum has a broad thickened border; the proximal edge is not 

 straight. The poster of the apertura bears a wide little deep sinus. 



Genotype. — &ch kellozoon {Retepora) imperati Busk, 1884. Recent. 



The spiramen (reteporidan pore of Waters) is replaced by a 

 pseudospiramen which is a groove in the proximal lip of the peri- 

 stomice. 



