. Bulletin of the British Museum (Natural History). 200 N. J. MORRIS & R. J. CLEEVELY. Fig. 4 Phanerotinus cnstatus (Phillips). The dorsal emargination is preserved in an external mould of the early whorls. The growth lines on the base of the whorl and the peripheral spines of several whorls are also shown. Note that the spines are close to the inner margin of the succeeding whorl. BM(NH) G72, x 11. Carboniferous Limestone, locality not recorded; James Tennant collection, purchased from his executors 1881. The upper lip has a small V-shaped dorsal emargination, which bears short hollow spi
. Bulletin of the British Museum (Natural History). 200 N. J. MORRIS & R. J. CLEEVELY. Fig. 4 Phanerotinus cnstatus (Phillips). The dorsal emargination is preserved in an external mould of the early whorls. The growth lines on the base of the whorl and the peripheral spines of several whorls are also shown. Note that the spines are close to the inner margin of the succeeding whorl. BM(NH) G72, x 11. Carboniferous Limestone, locality not recorded; James Tennant collection, purchased from his executors 1881. The upper lip has a small V-shaped dorsal emargination, which bears short hollow spines directed towards the aperture; the prominent fine and evenly-spaced growth lines are opisthocyrt on either side of this 'selenizone', crossing the dorsal spine and extending progressively forward over the top of the peripherarspines, but turning sharply backwards on their lower surface. The spines are more frequent on the inner whorls than the later ones, but are much smaller. The presence of the spines markedly increases the diameter of the shell, which comparison of the following measurements, taken wherever preservation permitted, confirms. Diameter of steinkern Diameter with spines Height of steinkern Width of steinkern G 186 G72 LZB34 LZB29 105 mm 97 mm 150 mm 152 mm 195 mm 160 mm 245 mm — — 22 mm — — 38 mm Discussion. The limited number of available specimens of this remarkable gastropod and their poor preservation have prevented a satisfactory interpretation of its biology. Yet, despite these drawbacks, earlier authors have assigned Phanerotinus cristatus to the 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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