326 



MOLLUSCOIDEA— BEYOZOA 



PHYLUM V 



reaching tlie centre. Zooecial tubes opening on tlie two opposite sides of plates. 

 Depressed interspaces occupied by interstitial cells. Cretaceous. 



Radiopora d'Orb, Zoariuni massive witli zooecia arranged in radial series separated 

 by wide areas of mesopores. Cretaceous. 



Actinotaxia Hamm ; Trochüiopora, Tholopora Gregory ; SemimuUicavea, Multi- 

 cavea, Pyricavea d'Orb. Cretaceous. 



Family 15. Cerioporidae Busk. 



Zoaria multiform^ encriisting, lamellar, hulbous, lohate, digitate or ramose, composed 

 of closely arranged thin-iualled tubes. The lauer sometimes completely separated hy 

 angular interstitial cells. Walls of neighhouring tubes tJioroughly amalgamated and 

 pierced by numerous pores. Trias to Recent. 



Under this family are grouped the genera referred by Gregory to the Cerioporidae in 

 which mesopores are absent, the Heteroporidae with numerous mesopores, and the Zonatulidae 

 with mesopores grouped in spiral bands or rings. The internal and other features of these 

 three families are identical, and it is believed that the distribution of the mesopores is in 

 this case not of family importance. Gregory assigns these three families, as well as the 

 Radioporidae, to the Trepostomata, but, although it is triie that they resemble the earlier 

 Order in some features, the complete amalgamation and porous nature of their walls is 

 exactly the same as in typical Cyclostomata. 



omulticava d'Orh. {Semicava d'Orb.; Reptocea Keeping) (Fig. 459). Zoarium 



massive or branched, multi- 

 lamellar ; zooecia sliort, meso- 

 pores absent. Cretaceous. 



Defranciopora Hamm. 

 Zoarium of superposed, discoid 

 colonies ; mesopores wanting. 

 Cretaceous. 



Ceriopora Goldfuss (Oerio- 

 cava d'Orb.). Zoarium massive 

 or branched, witli long zooecia 

 and no mesopores. Trias to 

 Recent. 



Heteropora BlainvlUe (Fig. 

 460). (Polytrema, Grescis, 

 Nodicrescis d'Orb.). Like Ceriopora but with numerous mesopores. Jurassic to 

 Recent. 



Biflabellaria Pergens. Like Hetero- 

 pora but zoarium bifoliate. Cretaceous. 



Zonatula Hamm. Zoarium dendroid 

 with spiral or annular constrictions 

 composed of mesopores. Cretaceous. 



Plethopora Hagw. Like Zonatula but 

 zooecia open in knob-like elevations. 

 Cretaceous. 



Ghilopora Haime. Jurassic. Multi- 

 zonopora d'Orb. ; Bivestis Hamm ; Spar- 

 sicytis Filliozat. Cretaceous. 



Fio. 459. 



ReptomuUicava spongites Goldf. Greensand ; Essen. A, Zoarixim, i/i 

 B, C, Upper and lower sides, enlarged. 



Suborder E. 



CERAMOPOROIDEA, 



nom. nov. 



wmWmWsm 



Fig. 460. 



This new suborder is proposed for the ^aiS^SfaTeÄS "Ä z'LaHu^T 'clveSi 



PaleOZOic Bryozoans included in tlie two section. D, Upper siuface, enlarj^ed. 



