. Bulletin of the British Museum (Natural History). PEBASIAN MOLLUSCAN FAUNAS 223. Figs 186-187 Vitrinella helicoidea C. B. Adams, type species of Vitrinella (). Recent beach drift; Miami, Florida; presented and identified by D. R. Moore; BMZD 1984240 (2 shells from sample). 186; a, b, c, d, respectively apical, rear, side and (to show umbilical ridge) obliquely ventral views, all x 25; e, apex, showing aperture of larval shell at about ten o'clock, x 200. 187; a, front, x 40; b. oblique view of apex showing larval aperture at about eight o'clock, x 200. The Pcbasian fossil mat
. Bulletin of the British Museum (Natural History). PEBASIAN MOLLUSCAN FAUNAS 223. Figs 186-187 Vitrinella helicoidea C. B. Adams, type species of Vitrinella (). Recent beach drift; Miami, Florida; presented and identified by D. R. Moore; BMZD 1984240 (2 shells from sample). 186; a, b, c, d, respectively apical, rear, side and (to show umbilical ridge) obliquely ventral views, all x 25; e, apex, showing aperture of larval shell at about ten o'clock, x 200. 187; a, front, x 40; b. oblique view of apex showing larval aperture at about eight o'clock, x 200. The Pcbasian fossil material is almost certainly not so well preserved as Pondcr's specimens of Glacidorbis, but the embryonic shell of V. hauxwelli shows no trace of any granular surface. It is much smaller, and is clearly delineated from the teleoconch by a very strong growth line. The growth lines in Glacidorbis appear to be virtually orthocline and almost straight, whilst those of the fossils are more prosocline and markedly sinuous. Vitrinellidae with which the Pcbasian fossils should be compared are Vitrinella , V. (Vitrinellops), V. (Striovit- rinella), Cochliolepis and C. (Tylaxis). Doubt must remain about the value of some of the distinctions between these taxa, which seem to be both arbitrary and unnecessary. Neither Vitrinella nor its type species were figured in then original descriptions (C. B. Adams 1850). I'he true identity ot Cochliolepis is uncertain, as the type specimens of the type species were destroyed. There is no uniformity of opinion as to its correct identification, a*- the original illustra- tions (Stimpson 1858) lacked detail. Vitrinella C. B. Adams (1850; 3) has as type species Vitrinella helicoidea C. B. Adams (1850: °0. b> subsequent designation of Bush (1897; 122): living. Jamaica, probably. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrati
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