326 



MOLLUSCOIDEA— BEYOZOA 



PHYLUM V 



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

 DejDressecl interspaces occupied by interstitial cells. Cretaceous. 



Radiopora d'Orb. Zoarium massive with zooecia arranged in radial series separated 

 by wide areas of mesopores. Cretaceous. 



Actinotaxia Hamni ; Trocliiliopora, Tholopora Gregory ; SemimuUicavea, Multi- 

 cavea, Pyricavea d'Orb. Cretaceous. 



Family 15. Cerioporidae Busk. 



Zoaria multiform, encrusting, lamellar, bulbous, lobate, digitate or ramose, compiosed 

 of closely arranged thin-ivalled tubes. The latter sometimes completely separated by 

 angular interstitial cells. IValls of neighbouring tubes thoroughly amalgamated and 

 pierced by numerous pores. Trias to Recent. 



Under this family are grouped tlie 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 otlier features of tliese 

 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 true 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. 



Reptomulticava d'Orb. (Semicava d'Orb.; Reptocea Keeping) (Fig. 459). Zoarium 



massive or branched, multi- 

 lamellar ; zoQJcia short, meso- 

 pores absent. Cretaceous. 



Defranciopora Hamm. 

 Zoarium of suj^erjjosed, discoid 

 colonies ; mesopores wanting. 

 Cretaceous. 



Geriopora Goldfuss (Gerio- 

 cava d'Orb.). Zoarium massive 

 or branched, with long zooecia 

 and no mesopores. Trias to 

 Recent. 



Heteropora Blainville (Fig. 



460). {Polytrema, Grescis, 



Like Geriopora but with numeroiis mesopores. Jurassic to 



Fio. 459. 



Reptomulticava spongites Goldf. Greensand ; Essen. A, Zoarium, V] 

 B, C, Upjier and lower aides, enlarged. 



Nodicrescis d'Orb.). 

 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- 

 aonopora d'Orb. ; Bivestis Hamm ; Spar- 

 sicytis Filliozat. Cretaceous. 



Suborder E. 



CERAMOPOROIDEA, 

 nom. nov. 







€«^^j^fi; 



Fio. 400. 



This new suborder is proposed for the 

 Paleozoic Bryozoans included in the two 



Hctrroporn pustulosa Miclu (heat Oolite ; Ranville, 

 Calvados (after Hainio). A, I!, 'Aoarmm, '/i- <^, Vertical 

 section. D, lljiper surface, enlarged. 



