GASTROPODS: EULIMIDAB, MARGINELLIDAE TO HELMINTHOGLYPTJDAE42


 Cavolina (Cavolina) cf. C. ventricosa (Guppy) Plate 63, figures 1-1, 12
 Small, both sides strongly inflated, dorsal side m-ore strongly than ventral1. Little shell material remaining onl ventral side. Dorsal side bearing a low, central swelling of moderate width, set off by wide, shallow depression. Apertural part far overhanging ventral side. Posterior lateral margins upturned. Apical spine wide-based, bent toward dorsal side, tip missing.
 Height 3.9 mmn, width 4.3 mm, diameter 3.3 mm (figured specimen).
 Ani early collection from the Mount Hope area containis another specimi-en of Cavolia s.s., evidently representing a new species. It is in poor condition. Though much of the dorsal side is preserved, it is badly cracked and bits of shell are missing.
 The exceptionally strong inflation of the dorsal side is the most noteworthy feature of this species. In general features it resembles C. ventricosa (Woodring, 11928, p. 114, pl. 1, figs. 8, 9; Collins, 1934, p. 184, p1. 7, figs. 16-18; B~owden formation, Jamaica), but the dorsal inflation is greater; the central swelling is wider; and a pair of minor lateral swellings is absent.
 Occurrence: Upper part of Gatun formation middlee Miocene), eastern area, locality 177.

 Family ELLOBIIDAE
 Subfamily ELLOBIINAE Genus Ellobium Rdding
 RL~ding, Museum Boltenianum, p. 105, 1798. Type (logotype, Winckworth, M.Nalacolog-.. Soc. London, v. 26,
 p. 139, 19,45) : Jilloium midw Riiding ( iVohtta aurismida3 Gmelin =Bulla aurismidwv Linn6) living, western
 Pacific Ocean.
 Winckworth attributed thle type designation to Gray (1847, p. 179), but that designation was not in suitable form for Ellobium. The type species is gigailtic compared with the American species.

 Ellobiuam aff. E. pellucens (Menke) Plate 48, figure 24
 Of medium size, moderately slender. No trace of sculpture apparent. Columella bearing two folds: a basal fold and one some distance above it.
 H-eight 17.5 mm, diameter 8 min (figured specimen).
 The La B3oca formation yielded the first American fossil representative of the salt-marsh pulmoniate genus Ellobiuin. It is in poor~ condition: partly crushed aild somle shell is missing. In outline and lack of sculpture it closely resembles immnnature specimens of the living Caribbean species E. pelluce'ns Menke (1828, p. 78). If it were known to be mature, it would be appropriate


to consider it to be a small predecessor of the nominate form. The original aragonite is replaced by calcite, but if this fossil were related to thc eastern Pacific K. stagnalis (d'Orbigniy) (1835, p. 23), a'- least a trace of the fine, crimped sculpture of that species should be apparent.
 Occurrence: Lai Boca formation (early Miocene), locality 116a.
 Family HELMvINTI{OGLYPTIDAE
 Subfamily XANTHONYCINAE
 Genus Averellia Ancy
Ancy, [Letter to editor], Conchologists' Exchange, v. 1, p. 54,
 1887. Substitute name for Cwrlospira Aiicy, 1886, not
 Cwlospira Hall, 1863.
Type (orthotype of Cawlospira Ancy, 1886): Helix macneili
 Crosse, living, Nicaragua and Costa Rica.
 Subgenus Lecallia Woodriug, n. subgeu.
Type: Avcrcllia (Lecallia) stcwvarti Woodring,, n. sp., marine
 member of Bohiio (?) formation, late Eocene or early
 Oligocene, Canal Zone.
 Of medium size, flattened discoidal, periphery asymmietrically rounded. Umbilicus about a third of shell diamecter. Whorls 414, slowly enlarging in diameter, upper surface slightly inflated. Growth lines exagg~erated at intervals. Peristome missing.
 Lecallia is inferred to be related to Trichodiscina von Martens (1890-1901, p. 133, 1892, substitute name for lrictodisc'us Strebel and Pfeffer, 1880, not T'riehodiscus Ehrenberg, 1830; type (logotype of Ti'ichodiscus Strebel and Pfeffer, 1880) :Helix coactiliats F~rrusac, hlin, northern Mexico to Trinidad). Trichodiscina is currently assigned subgeneric rank under Avercilia. The anatomy of the type species of Averellia is unknown. Trhe upper surface of the shell is concave and the body -whorl near the aperture is creased by two strong internal lamellhT. The jaw and radula of the type species of Trichodiscima have been described (Baker, 1922, p. 57, pl. 17, figs. 7, 9) and the genitalia of a closely related species, A. cordovana (Pfeiffer) (Baker, 1927, p. 242, p1. 20, figs. 53-57). Lecallia is larger than the species of Trickodiscina and the upper surface of its whorls is flatter.

 Averellia (Lecallia) stewarti Woodring, n. sp.
 Plate 48, figures 9, 14, 18
 Features of tihe nionotypic, subgenus.
 Height 6 mm, diameter 15.5 mim (type).
 Type: USNM\ 646088.
 Type locality: 41b (USGS 18839, East side of Palenquilla Point, head of cove north of triangulation station and southwest of Corozo Island, Canal Zone), marine member of lBohio (?) formation.


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