. Bulletin of the British Museum (Natural History). 122 PITT AND TAYLOR the branch diameter, and is surrounded by an exozone in which zooeciai walls thicken abruptly (Fig. 122). The keno- zooecia appear to be budded around the endozonal-exozonal boundary. Zooeciai walls are parallel-sided ( not monili- form) and show well-developed rounded laminations in longitudinal section in the exozone. Some of the autozooecia are partitioned by thin diaphragms in the endozone. Most diaphragms are orally flexed where they meet the zooeciai walls (basal diaphragms), but some near the outside o
. Bulletin of the British Museum (Natural History). 122 PITT AND TAYLOR the branch diameter, and is surrounded by an exozone in which zooeciai walls thicken abruptly (Fig. 122). The keno- zooecia appear to be budded around the endozonal-exozonal boundary. Zooeciai walls are parallel-sided ( not monili- form) and show well-developed rounded laminations in longitudinal section in the exozone. Some of the autozooecia are partitioned by thin diaphragms in the endozone. Most diaphragms are orally flexed where they meet the zooeciai walls (basal diaphragms), but some near the outside of the endozone are aborally flexed. Measurements (ranges of mean values from four colonies, except for ooeciopore). TAM, 0-07-0 08 mm; TPM, 011- 0-13 mm; KAM, 0 03-0 05 mm; width of kenozooecial frontal surface area, 0-10 mm; GDL, 0-60-2-00 mm; GW, 0-90-1-50 mm; LOPM, 0-03 mm; TOPM, 0 03 mm. Remarks. Canu & Bassler (1926) used three separate species names for material from Faringdon which is here described as T. multiporosa. One of these species, Sparsicavea irregulare d'Orbigny, originally described from the Albian of the Ardennes, is difficult to intepret from d'Orbigny's figures and description, but may possibly be a senior synonym of T. multiporosa. T. densa Canu & Bassler was distinguished from T. multiporosa by the smaller size of the kenozooecia ('meso- pores'). This difference is, however, gradational and seems related to the ontogenetic stage of the kenozooecia. Genus CL/lf/5'/l d'Orbigny, 1853 Type SPECIES. Ceriopora heteropora d'Orbigny, 1850, by sub- sequent designation of Gregory, 1899; Cenomanian of France. Remarks. The vinculariiform branches of species of Clausa are characterized by the presence of numerous polygonal kenozooecia, sometimes occluded by terminal diaphragms, surrounding the circular, open apertures of the autozooecia. These kenozooecia have often been referred to as 'dactyl- ethrae', and Gregory (1896) used their occurrence to define a cycl
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