. Bulletin of the British Museum (Natural History). . Fig. 21. Pelaloconchus sculpturatus. Specimen, Stanford Univ. collection, from the Miocene of Trinidad, with internal laminae showing in the broken section of one coil Xj. Fig. 22. _ P. {Macrophragma) macrophragma, sketch of lectotype, to illustrate coiline Mazatlan, X2. () Reg. No. Fig. 23. P. (M.) macrophragma. Operculum. Stanford Univ. collection. x 13. Fig. 24. Same, nuclear whorls. West Mexico. XI2-5. Fig. 25. Detail of columellar laminae. Stanford Univ. collection, Oaxaca, Mexico X6. Subgenus MACROPHRAGM
. Bulletin of the British Museum (Natural History). . Fig. 21. Pelaloconchus sculpturatus. Specimen, Stanford Univ. collection, from the Miocene of Trinidad, with internal laminae showing in the broken section of one coil Xj. Fig. 22. _ P. {Macrophragma) macrophragma, sketch of lectotype, to illustrate coiline Mazatlan, X2. () Reg. No. Fig. 23. P. (M.) macrophragma. Operculum. Stanford Univ. collection. x 13. Fig. 24. Same, nuclear whorls. West Mexico. XI2-5. Fig. 25. Detail of columellar laminae. Stanford Univ. collection, Oaxaca, Mexico X6. Subgenus MACROPHRAGMA Carpenter, 1857 (Text-figs. 22-25) Polyphragma Vaillant, 1871 [not Quatrefages, 1866] ; Petaloconchus. s. s. of authors. Coiling regular, especially in the early whorls, described by Carpenter as "like a Tmntella squeezed sideways ". Sculpture cancellate, but with the longitudinal ribs tending to be predominant and sub-carinate. Nuclear whorls two to four, ivory white to waxy yellow, conic to cylindrical Adult shell medmm to dark brown in colour. Operculum concave, with an upstand- ing spiral lamella of one or two volutions, diameter less than that of the aperture resembling that of Vermetus [Thylaeodus) in form. The shells are either solitary or colonial and are mostly smaller in size than in other vermetid groups except Vermetus [Thylaeodus), which tliey closely resemble except for more regular coiling and the internal spiral lamellae. Scars of broken feeding tubes are common and may recur at regular intervals along the coil. Assignable species : P. [M.) cereus Carpenter, 1857. Philippines. P. (M.) cochlidiiim Carpenter, 1857. Australia. P. (M.) complicatus Dall, 1908. Panama Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original British Museum (Natural History). London : BM(NH)
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