. Bulletin of the British Museum (Natural History). 144 PITT AND TAYLOR. Figs 166-168 Charixa Ihuydi (Pitt). Fig. 166, BM(NH) D55068; 166A, x 39; 166B, detail of cement encrusted zooecia, x 104. Fig. 167, BM(NH) D54167, typical irregular arrangement of zooecia, x 50. Fig. 168, BM(NH) D54191, part of a worn colony encrusting an echinoid spine, showing a row of three caudate zooecia following a vertical groove in the spine (centre), x 34. developed into a pseudolunarium (Fig. 164D, E) sharply indenting the proximal edge of the aperture, particularly in zooecia close to maculae. The wid
. Bulletin of the British Museum (Natural History). 144 PITT AND TAYLOR. Figs 166-168 Charixa Ihuydi (Pitt). Fig. 166, BM(NH) D55068; 166A, x 39; 166B, detail of cement encrusted zooecia, x 104. Fig. 167, BM(NH) D54167, typical irregular arrangement of zooecia, x 50. Fig. 168, BM(NH) D54191, part of a worn colony encrusting an echinoid spine, showing a row of three caudate zooecia following a vertical groove in the spine (centre), x 34. developed into a pseudolunarium (Fig. 164D, E) sharply indenting the proximal edge of the aperture, particularly in zooecia close to maculae. The widely spaced apertures are arranged more-or-less in quincunx in intermacular areas. Apparent alveoli (Fig. 164D) have small, sunken apertures with inwardly-sloping sides, and are about ()-02-0-03 mm in diameter. Brood chamber, only observed fractured in one poorly- preserved specimen (D58207), is cavernous and is pierced by autozooecia which apparently support the roof. In tangential section the zooecial walls are thick, and indistinctly laminated or granular in appearance, with clearer linings visible in some of the autozooecia. Measurements. LAM, mean 0 06 mm; TAM, mean 0-05 mm. Remarks. P. boardmani is clearly distinguished from other early Cretaceous cyciostomes by the pustulosc frontal calcifi- cation and pseudolunaria. There is a slight resemblance to the Valanginian species Reptocavea rugosa d'Orbigny, 1853, re- vised by Cotillon & Walter (1965; see also Walter 1972, Walter et al. 1975) as Petalopora rugosa (d'Orbigny), but this lacks these two characteristic features, and has autozooecial apertures about twice the size of those in P. boardmani. Only four specimens are known of P. boardmani. The holotype is a small colony encrusting a branch of an erect cyclostome, while one of the paratypes (BM(NH) D57712) is a large, hollow, flabellate colony which apparently encrusted an erect soft-bodied organism. Class GYMNOLAEMATA Allman, 1856 Order CHEILOSTOMATA Busk, 1852 Subor
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