of the British Jurassic Bryozoa. 293 



Order TREPOSTOMATA. 



Bryozoa in which the zoarium consists of prismatic or cylin- 

 drical zooecia which are arranged parallel to one another. 

 The zoarium is either massive or composed of encrusting or 

 erect lamina. 



The zooecia are either closely packed or separated by meso- 

 pores or by inter-zocecial vesicles. The zocesia begin as thin, 

 simple, immature Cyclostomatoid tubes. Diaphragms are 

 generally present. Generally dimorphic. 



Family Amplexoporidae. 



Diagnosis. — Trepostomata in which the zooecia are simple, 

 prismatic, or subcylindrical, with a well-marked divisional 

 line between the walls of adjoining cells. Mesopores absent. 

 (Aborted zooecia occur and sometimes resemble mesopores.) 

 Diaphragms horizontal. 



Genus CeriopoRA, Blainville, 1834. 



Diagnosis. — Amplexoporida? with prismatic or subcylin- 

 drical zooecia. Mesopores absent. Acanthopores absent. 

 Walls of zocecia thin. Diaphragms horizontal, numerous. 

 Zoarium branching or massive. 



Type species : (J. micropora, Goldfuss, 1829. 



1. Ceriopora globosa, Michelin, 1846. 



Ceriopora globosa, Michelin, 1846, Icon. Zoopb. p. 246, pi. lvii. 



fig. 5. 

 Monticidipora globosa, d'Orbigny, 1849, Prod. Pal. t. i. p. 323. 

 Reptonodicava globosa, d'Orbigny, 1852, Pal. franc., Terr. cr<St. t. v. 



p. 1015. 



Diagnosis. — Zoarium massive, either spherical or of irre- 

 gular lobed masses, generally with a broad base protected by 

 epitheca. The surface is level and ornamented with irregu- 

 larly scattered tubercles. 



Diaphragms abundant. 



Young zocecia are fairly abundant, and being smaller in 

 size resemble mesopores. 



Distribution. — England : Inferior Oolite — Bradford Clay. 

 Foreign : Bajocian and Bathonhin, France and Germany. 



2. Ceriopora arborescens, Waagen, 1868. 



Ceriopora arborescens, Waagen, 1868, Zone Amm. Soiverbyi, Geogu. 

 Pal. Beitr. Bd. i. Heft 3, p. 644, pi. xxxiii. fig. 2. 

 Ann. & Mag. N. Hist. Ser. 6. Vol. xvii. 21 



