GEOLOGY AND PALEONTOLOGY OF CANAL ZONE


narrower umbilical groove. T. precursor occurs in the early Miocene Tampa limestone of Florida.
 In Europe Tricolia is recognized in strata as old as Paleocene, but T. calypta is the earliest American species so far described.
 Occurrence: Marine member of Bohio(?) formation (ate Eocene or early Oligocene), Gatun Lake area, localities 40a, 40d.
 Family PHASIANELLIDAE?
 Tricolia? syntoma Woodring, n. sp.
 Plate 17, figure 47
 Small, strongly inflated, spire low, outline like that of a minute naticid. Columellar lip wide, its outer edge bearing a faint low narrow rim. Parietal callus thick, continuous with the columellar lip, its edge sharply defined. Umbilical groove very narrow, almost closed. Operculum unknown.
 Height 2.2 mm, diameter 2.2 mm (type).
 Type: USNM 561328.
 Type locality: 170a (USGS 8411, headwaters of 'Quebrada Cafna (Rio Caflo Quebrado), Panami, middle part of Gatun formation.
 The family and generic assignment of this minute species, represented by one specimen from the middle part of the Gatun formation, are doubtful. Some features suggest a low-spired Tricolia, but no species of Tricolia examined has a wide-rimmed columellar lip. The type and only specimen of "Eucosmia" lurida Dall (1897, p. 15, pl. 1, fig. 11) in the collection of the U. S. National Museum (a Recent shell from British Columbia) has a wide distinctly rimmed columellar lip, which is not shown on the poorly drawn aperture of Dall's illustration. This species, however, is probably a Homalopoma related to H1. subobsoletum (Willett) (1937, p. 63, pl. 25). Most species of Tricolia have a thin parietal callus that fades out on the parietal wall. Nevertheless some species have a moderately thick callus that joins the columellar lip. Despite its relatively narrow aperture, Tricolia? syntoma may represent an undescribed turbinid genus remotely related to Homalopoma.
 In outline Tricolia? syntoma suggests the Miocene Jamaican species Tricolia (Eulithidium) hadra Woodring (1928, p. 420, pl. 34, figs. 10, 11) and a minute Recent Cuban Tricolia described by Dall (1889, p. 351, pl. 19, fig. 10b) as "Phasianella (Eucosmia)" brevis d'Orbigny. Both species, however, have Tricolia-like apertural features.
 Occurrence: Middle part of Gatun formation (middle Miocene), western area, locality 170a.


 Family NERITIDAE
 Subfamily NERITINAE Genus Velates Montfort
Montfort, Conchyliologie syst6matique, v. 2, p. 355, 1810. 4 Type (orthotype): Velates conoideus (Nerita conoidea Lamarck=
 Nerita perversa Gmelin), Eocene, Paris Basin.
 Velates perversus (Gmelin), subspecies?
 Plate 14, figures 5-8
 Reaching a large size, ovid in ventral plan, apex moderately eccentric. Columellar lip bearing seven or. eight teeth. Callus deeply indented adjoining lower end of columellar lip and extending along inner border of outer lip, forming a wide rim.
 Approximate height 60 mm, restored diameter 100 mm (largest specimen). Height 22.5 mm, diameter 43.7 mm (larger figured specimen).
 Though Velates was found in limestone of the Gatuncillo formation at five localities, the only specimens showing the aperture are from locality 38 in the Rio* Casaya area. The shell of medium size shown on plate 14, figures 5, 7 is the largest of 18 collected at that locality. Twelve of the 18 have complete columellar lips, and on 9 the outer lip is preserved. The shells from locality 38, and the incomplete specimens from the other localities so far as they are preserved, closely resemble Lutetian Paris Basin specimens of Velates perversus (for citations and synonymy see Eames, 1952, p. 12). The fossils from Panama' that show the outer lip, however, have a wide rim along the inner border of the lip, whereas the rim is absent on 10 Paris Basin shells ranging in diameter from three to 70 millimeters.
 Katherine V. W. Palmer has kindly called my attention to the illustrations of V. balkanicus Bontscheff (1896 [1897], p. 380, pl. 6, figs. 1-5), based on specimens from the Eocene of Bulgaria. The illustrations show a rim on the outer lip like that on the specimens from Panama. Bontscheff (1896 [1897], p. 380, pl. 6, fig. 6) also described a variety (V. balkanicus marginatus) for specimens on which the thin edge of the outer lip extends around the entire aperture, bordering the callus. The teeth of the Bulgarian fossils are heavier than those of specimens from Panamd. It is doubtful whether the rim on the outer lip is an indication of close relationship.
 Velates has a range of Late Cretaceous to late Eocene. V. perversus is widely distributed in Eocene deposits from India to the Mediterranean region and the Paris Basin, reaching its acme in the middle Eocene. The genus is relatively rare in the American Eocene. Under the name V. schmideliana, V. perversus is recorded from


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