GASTROPODS: TROCHIDAE TO TURRITELLIDAE


most distinctive feature. On a few shells the suture on the last half of the body whorl descends more sharply than on the common form, producing a correspondingly higher spire.
 The more distinct depression on the umbilical callus lobe and the narrower groove at the outer edge of the ,lobe differentiate Tectonatica agna from T. pusilla (Say), which moreover is slightly larger. T. pusilla is the only fossil Tectonatica recorded from the Caribbean region (Woodring, 1928, p. 384, pl. 30, fig. 12). It now ranges from Massachusetts to Florida. A Recent West Indian species, possibly T. sagraiana (d'Orbigny) also lacks the callus depression. No Recent Panamic species is represented in the U. S. National Museum collection.
 Occurrence: Middle and upper parts of Gatun formation (middle and late Miocene). Middle part, eastern area, localities 146, 147b, 147f, 147g, 147h, 151, 153a. Upper part, eastern area, locality 177c; western area, locality 185 (identification doubtful).
 Subfamily POLINICINAE
 Genus Polinices Montfort
'Montfort, Conchyliologie syst6matique, v. 2, 1. 223, 1810. Type (orthotype): Polinices albus Montfort (==Natica mamnilaris
 Lamarck=Natica brunnea Link), Recent, West Indies.
 Incomplete and poorly preserved naticids from the Gatuncillo formation, the marine member of the Bohio(?) formation, and the Culebra formation are doubtfully referred to Polinices. The umbilical features of these fossils, most of which are molds, are not known.

 Polinices canalizonalis (Brown and Pilsbry) Plate 20, figures 7, 8
 Natica canalizonalis Brown and Pilsbry, Acad. Nat. Sci. Phila.
 Proc., v. 64, p. 508, pl. 22, fig. 10, 1913 (Miocene, Canal Zone).
 Of medium size, thick-shelled. Body whorl appressed at suture, strongly inflated below appressed area. Aperture small for size of shell. Apical whorl small. Faint microscopic spiral lineation visible on unworn parts of shell. Umbilicus wide. Umbilical rib strong on immature shells, somewhat flattened on mature shells, ending in a wide callus lobe. Parietal callus very thick, bearing a shallow transverse groove.
 Height 21 mm, diameter 18.7 mm (figured mature specimen). Height 11 mm, diameter 10 mm (figured immature specimen).
 Type: Acad. Nat. Sci. Phila. 3844.
 Type locality: Gatun Locks excavation, Canal Zone, middle part of Gatun formation.
 Polinices canalizonalis is the least abundant of the three Gatun species of Polinices. It also is the only one of the three that has a conspicuous umbilical rib.


The type is an immature shell (height 8.2 millimeters). The well-defined umbilical rib indicates alliance with a Recent Caribbean species labelled P. porcellanus (d'Orbigny) in the U. S. National Museum collection. The Recent species has a stronger rib and is less appressed at the suture. P. carolinianus (Conrad) (Mansfield, 1930, p. 127, pl. 19, fig. 1), which occurs in the Duplin formation of North Carolina and in deposits of late Miocene age in western Florida, is larger, less appressed at the suture, and has a stronger rib. A late Miocene species from Trinidad, P. boutakoffi Rutsch (1942, p. 139, pl. 6, figs. 7a, 7b), belottgs in this group of species characterized by a strong umbilical rib. According to Rutsch's illustrations, it is more inflated, less appressed at the suture, and has a deeper groove on the parietal callus.
 Occurrence: Lower middle, and upper parts of Gatun formation (middle Miocene). Lower part, locality 136a. Middle part, eastern area, Gatun Locks excavation (Brown and Pilsbry); western area, locality 161a. Upper part, eastern area, localities 177b, 177c.

 Polinices brunneus subclausus (Sowerby) Plate 20, figure 9
Natica subclausa Soeicrby, Geol. Soc. London Quart. Jour., v. 6,
 p. 51, 1850 (Miocene, Doniticea Republic).
Polinices subclausa (Sowerby), Brown and Pilsbry, Acead. Nat.
 Sci. Phila. Proc., v. 63, p. 360, 1911 (Miocene, Canal Zone).
 Maury, Bull. Am. Paleontology, v. 5, no. 29. p. 136, pl. 23, fig. 14, 1917 (Miocene, Dominican Republic). Olsson, idem, v. 9, no. 39, p. 157, pl. 13, figs. 16-17, 1922 (Miocene, Costa Rica, Canal Zone). Hodson, Hodson, and Harris, idem, v. 13, no. 49, p. 69, pl. 36, fig. 5, 1927 (Miocene, Jamaica).
 Anderson, Calif. Acad. Sci. Proc., 4th ser., v. 18, no. 4, p. 124,
 1929 (Miocene, Colombia, Canal Zone).
Polinices srunnea subclausa (Sowerby), Woodring, Carnegie Inst.
 Washington Pub. 385, p. 385, pl. 30, fig. 13, 1928 (Miocene,
 Jamaica); see this publication for other citations.
?Polinices (Mammilla) cf. brunnea Link, Weisbord, Bull. Am.
 Paleontology, v. 14, no. 54, p. 29, pl. 9, fig. 12, 1929 (Miocene,
 Colombia).
 Of meditu size, thick shelled. Whorls strongly and smoothly appressed at suture. Apical whorl small. Umbilicus ttsoderately narrow; tmbilical rib almost flat. Umbilical callus lobe narrow, slightly widened by umbilical rib. Parietal callus very thick, bearing a shallow transverse groove.
 Height 20.3 tote, diameter 16.7 tm (figured specite en).
 Type material: British Mus., Natural History, Geol. Depart., Geol. Soc. London 12826 (6 syntypes).
 Type locality: Dominican Republic, Miocene.
 This Polinices is fairly cotmton in the middle part of the Gatun formation at locality 161c, west of Gatun Dam, and occurs at other localities, all in the middle part of the Gatun formation. The groove on the


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