of the British Jurassic Bryozoa. 293 



Order TREPOSTO.MATA. 



Brjozoa in which tlie zoariura consists of prismatic or cylin- 

 drical zooecia wliich are arranged parallel to one another. 

 The zoarium is either massive or cotnposed of encrusting or 

 erect lamina. 



The zocecia are either closely packed or separated by meso- 

 pores or by inter-zooecial vesicles. The zooecia begin as thin, 

 simple, immature Cv^clostomatoid 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. — Amplexoporida3 with prismatic or subcylin- 

 drical zooecia. Mesopores absent. Acanthopores absent. 

 Walls of zooecia thin. Diaphragms horizontal, numerous. 

 Zoarium branching or massive. 



Type species : C. micropora^ Goldfuss, 1829. 



1. Ceriopora glohosa, Michelin, 1846. 



Ceriopora globosa, Michelin, 1846, Icon. Zoopb. p. '2-icQ, pi. Ivii. 



fig. 5. 

 Monticulipora ghbosa, d'Orbigny, 1849, Prod. Pal. t. i. p. 323. 

 Reptonodicava globosa, d'Orbigny, 1852, Pal. fran?., Terr. crt5t. 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 zooecia are fairly abundant, and being smaller in 

 size resemble mesopores. 



Distribution. — England : Inferior Oolite — Bradford Clay. 

 Foreign : Bajocian and Bathonian, France and Germanj-. 



2. Ceriopora arborescensj Waagen, 1868. 



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

 Pal. Beitr. Bd. i. Heft 3, p. 044, pi. xxxiii. fig. 2. 



Ann. (£• Mag. N. Ilist. iSer. 6. Vol. xvii. 21 



