. Bulletin of the British Museum (Natural History). . Figs 10-12 Voigtopora calypso (d'Orbigny). Fig. 10, BM(NH) D577: and a left lateral zooecium which emerges from the protoecium, x D57394, lateral ramification, x 40. Fig. 12, BM(NH) D Range. Bajocian to Recent. Stomatoporina alternata sp. no v. Figs 13-15 HOLOTYPE. BM(NH) D55352, Little Coxwell Pit; Gaster Colin. Paratypes. BM(NH) D55348, D53225, Little Coxwell Pit, Taylor Colin; B1935 (2 colonies on Neuropora sp.), Little Coxwell Pit, Lee Colin. Name. 'By turns'. Description. Zoarium encrusting, initially uniserial (Fig. 14A) wit
. Bulletin of the British Museum (Natural History). . Figs 10-12 Voigtopora calypso (d'Orbigny). Fig. 10, BM(NH) D577: and a left lateral zooecium which emerges from the protoecium, x D57394, lateral ramification, x 40. Fig. 12, BM(NH) D Range. Bajocian to Recent. Stomatoporina alternata sp. no v. Figs 13-15 HOLOTYPE. BM(NH) D55352, Little Coxwell Pit; Gaster Colin. Paratypes. BM(NH) D55348, D53225, Little Coxwell Pit, Taylor Colin; B1935 (2 colonies on Neuropora sp.), Little Coxwell Pit, Lee Colin. Name. 'By turns'. Description. Zoarium encrusting, initially uniserial (Fig. 14A) with zooccial apertures opening on one side; later biserial, with zooecia budding alternately to the left and right sides of the narrow branches (Fig. 13), which zigzag gently. Branches are 0-12 to 0-25 mm wide and bifurcate dichoto- mously at 60°-90°. Both daughter branches are biserial. Internodes are generally long, BM(NH) D55348 preserves the colony origin and about 16 generations of zooecia in a branch 3 mm long which does not bifurcate. Zooecia are small, short in the early stages of the zoarium but longer in later stages, slender, proximally tapering, with circular apertures. Peristomes are offset from the midline of the branches and slightly raised. Pseudopores arc not clearly ; lOA, ancestrula (protoecium arrowed) giving rise to a distal zooecium 9; lOB, bifurcation and lateral ramification, x 32. Fig. 11, BM(NH) '418, oblique view of zooecia with long peristomes, x 32. visible in the poorly-preserved material available. The ancest- rula, known from two abraded examples, is about 0-27 mm long and has an apertural diameter of 0-07 mm and a protoecium 012 mm in transverse width. Gynozooecia have not been observed. Measurements. TAM, 0-04^-06 mm; TPM, 0-07-0-09 mm; FWL, 0-38-0-60 mm; FWW (proximal), 0-12-0-15 mm. Remarks. This new species appears to be the only described Cretaceous stomatoporid with a biserial budding pattern of regularly alternating, zigzag zooecia.
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