GEOLOGY AND PALEONTOLOGY OF CANAL ZONE


 parietal callus is relatively deep on some small speci-. mens. The largest Gatun shells are half as large as the largest from the Miocene of the Dominican Republic and Bowden, Jamaica (height 40 millimeters), and are much smaller than large specimens of the Recent Caribbean P. brunneus proper (height 50 millimeters). Like the Miocene fossils from the Dominican Republic and Jamaica, the Gatun fossils have a slightly narrower umbilicus than Recent shells of the same size. The fairly wide umbilicus of Weisbord's Polinices cf. P. brunnea indicates,however,that the Miocene form cannot consistently be distinguished by the width of the umbilicus. Recent shells that are not worn show a faint microscopic spiral lineation, which has not been observed on the fossils from the Canal Zone, the Dominican Republic, and Jamaica. The apparent absence of lineation on the fossils, however, may be due to slight wear. A small form of P. brunneus subclausus from the Miocene of Banana River, Costa Rica, has faint spiral lineation and also has a deep groove on the parietal callus, as shown by Olsson's illustrations.
 A form of P. brunneus subclausus that has a notch between the parietal callus and the umbilical callus lobe has been recognized in the Miocene of Venezuela and Jamaica, and has been named P. subclausa lavelana F. Hodson (Hodson, Hodson, and Harris, 1927, p. 69, pl. 36, fig. 8, pl. 37, figs. 12, 14).
 Polinices nelsoni Olsson (1932, p. 208, pl. 24, figs. 8, 10), which is more slender than P. brunneus and has a narrower ambilicus, is a late Miocene Peruvian relative of P. brunneus, but no close allies are known to be living in the Panamic region.
 Occurrence: Middle part of Gatun formation (middle Miocene), eastern area, localities 155b, 155c; western area, localities 161 (immature, identification doubtful), 161c, 161d, 170 (immature, identification doubtful). Cercado and Gurabo formations (middle Miocene), Dominican Republic. Bowden formation (middle Miocene), Jamaica. Middle Miocene, Costa Rica. Miocene, Bolivar, Colombia.
 Polinices stanislas-meunieri Maury
 Plate 21, figures 11-14
Polinices stanislas-meanieri Maury, Bull. Am. Paleontology,
 v. 5, no. 29, p. 136, pl. 23, figs. 15-16, 1917 (Miocene, Dominican Republic). olsson, idem, v. 9, no. 39, p. 157, pl. 13, fig. 7, 1922 (Miocene, Costa Rica). Maury, idem, v. 10, no. 42, p. 240, pl. 40, fig. 7, 1925 (Miocene, Trinidad). Anderson, Gallf. Acad. SCl. Proc. 4th ser., v. 18, no. 4, p. 124, 1929 (Mioceae, Columbia).
Polinices stanislas-meunieri venezuelana F. Hodson, Bull. Am. Paleontology, v. 13, no. 49, p. 70, pl. 37, figs. 10, 15, 1927 (Miocene, Venezuela).
Not Polinices stanislas-mncunieri Maury, Li, Geol. Soc. China Bull., v. 9, p. 267, pl. 6, fig. 48, 1930 (Miocene, Panama Bay; =P. uber (Valenciennes) and P. rapulum limit Pilsbry, fide


 Pilsbry, Acad. Nat. Sci. Phila. Proc., v. 83, p. 432, 1931,
 Recent, Panama Bay).
 Polinices springvalensis Maury, Bull. Am. Paleontology, v. 10,
 no. 42, p. 241, pl. 40, fig. 6, 1925 (Miocene, Trinidad).
 Moderately large, moderately thick-shelled, moderately slender to strongly inflated. Whorls not appressed at suture, except near outer lip or on most of body whorl of large specimens. Apical whorl small. Microscopic spiral lineation distinct on unworn shells. Umbilicus and umbilical callus lobe narrow. Parietal callus moderately thick, much wider than umbilical lobe, bearing a faint to distinct transverse groove on immature shells.
 Height 43.5 mm, diameter 33 mm (figured large slender specimen). Height 32.5 mm., diameter 28 mm (figured inflated specimen).
 Type: Cornell University 36931.
 Type locality: Rio Cana, Dominican Republic, Gurabo (?) formation (middle Miocene).
 Polinices stanislas-meunieri is the most widespread of the Gatun species of Polinices. It is locally common in the lower part of the formation, but many of the specimens are relatively slender, like that shown on plate 21, figure 14. The large figured specimen (pl. 21, fig. 13) was collected by T. F. Thompson. The umbiical rib is so flat that it is virtually absent. Therefore the narrow umbiical callus lobe widens very slightly. The umbiicus is of varying width on immature shells, and is practically closed on one from locality 136 (height 6 millimeters). The transverse groove on the parietal callus is absent on shells of large and medium size, and generally is faint on small shells.
 Differentiation of P. stanislas-meunieri venezuelanus appears to be unwarranted. P. springvalensis is a shouldered form of P. stanislas-meunieri, but is not much more strongly shouldered than the Gatun specimen shown on plate 21, fig. 12. The early Miocene Costa Rican P. eminuloides (Gabb) (1881, p. 339, pl. 44, fig. 4) probably is related to P. stanislas-meunieri. The type, and only specimen, is high spired; the umbilical area is not completely exposed; and the parietal callus is damaged.
 P. stanislas-meunieri is widely distributed in the Miocene of the Caribbean region, but has no living. allies there. It is closely related, however, to the Recent Panamic P. uber (Valenciennes). P. stanislasmesnieri is not much more than half as large, but its parietal callus is thicker than that of specimens of P. uber of the same size, indicating maturity. The outline of P. stanislas-meunieri ranges from strongly and smoothly inflated to moderately slender, whereas that of P. uber is more uniformly strongly and smoothly inflated.


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