'1


GEOLOGY AND PALEONTOLOGY OF CANAL ZONE


94


 There are no known close allies of this species in Caribbean and Panamic waters. S. maculatum (Say), a Recent Floridian and West Indian species, has a narrower base, thinner columellar lip and parietal callus, and weaker sculpture.
 The small incomplete Sinum from the Miocene of Jamaica, so far as it goes, has the characters of S. euryltedra.
 Occurrence: Lower part of Gatun formation (middle Miocene), locality 137a. Bowden formation (middle Miocene), Jamaica.
 Sinum gabbi (Brown and Pilsbry) Plate 21, figures 3, 6
 Sigaretus (Eunaticina) gabbi Bron and Pilsbry, Acad. Nat. Sci.
 Phila. Proc., v. 64, p. 509, pl. 22, fig. 13, 1913 (Miocene,
 Canal Zone).
 Minum quirusanumn F. Hodson, Bull. Am. Paleontology, v. 13,
 no. 49, p. 67, pl. 36, figs. 10, 12, 1927 [Miocene (OligoceneMiocene of Hodson), Zulia, Venezuela].
 Reaching a large size, not depressed, body whorl strongly inflated. Spire low or relatively high. Protoconch of 2)) smooth slowly enlarging whorls. Sculpture of narrow closely spaced spiral threads of two or three orders. Spirals of early whorls variably crinkled by growth lines. A very narrow umbilical groove lies behind posterior part of everted columellar lip of adult shells. Immature shells umbilicate.
 Height 23 mm, diameter 23 mm (figured specimen). Height 27 mm, diameter 24 mm (largest complete specimen). Estimated diameter 35 mm (largest specimen, incomplete).
 Type: Acad. Nat. Sci. Phila. 3845.
 Type locality: Gatun Locks excavation, Canal Zone, middle part of Gatun formation.
 The type is a very small shell 6.5 millimeters high. The largest complete specimen (height 27 mm), collected at locality 175, has a higher spire than the others, but is associated with a smaller low-spired shell. That this species reaches a considerably larger size is shown by half of a body whorl (locality 176), which indicates a diameter of about 35 millimeters. The Venezuelan S. quirosanum is small, agreeing with S. gabbi in outline and sculpture, and may represent a small early Miocene race of S. gabbi. S. nolani Maury (1917, p. 139, pl. 24, fig. 1), a species that occurs in the Gurabo formation of the Dominican Republic, is more inflated than S. gabb.
 S. gabbi is a nondepressed species related to the Recent Peruvian S. concavum (Lamarck), the largest species of the genus (height 48 mm). The fossils, except the high-spired specimen, have a similar outline, but have spirals of less uniform width. No similar species is living in the western Atlantic.


 Occurrence: Middle and upper parts of Gatun formal. tion (middle Miocene). Middle part, eastern area localities 147b, 155, 155a, 155b, 155c (very small), 157 Upper part, eastern area, localities 175, 176, 177c.
 Subfamily GLOBULARIINAE
 Data concerning the anatomy of Cernina fluctuat (Sowerby), the only surviving globularine, are desirable as a basis for consideration of the subfamily or family status of that species and its numerous fossil allies.
 Wrigley (1946, p. 88) has proposed a useful terminology for features in the umbilical region and on the columellar lip of globularines. The sheath (the limbe of French authors and the callus or fasciole of American authors) is the shell layer emerging from the umbilicus of umbilicated species. Its outer edge is designated the rim. The downward extension of the parietal callus, overlapping the sheath, is designated the lobe of the columellar border, or simply the lobe. The outer edge of the lobe, where it overlaps the sheath below the umbilicus, is either fairly sharp or indefinite.. The sheath of some nonumbilicated species, such as Globularia sigaretina (Lamarck), is as well defined as: that of umbilicated species, but the umbilicus is represented only by a slight depression at the posterior end of the sheath, formed by the outer edge of the lobe. On other nonumbilicated or narrowly umbilicated species a sheath is not recognizable. If present, it is concealed by the lobe, which forms an everted columellar lip that has an outer edge as sharp as a rim.
 Genus Globularia Swainson
Swainson, A treatise on malacology, p. 345, 1840. Type (logotype, Herrmannsen, Indicis generum malacozoorum,
 v. 1, p. 480, 1847): Natica sigaretina Lamarck, Eocene,
 Paris basin.
 Subgenus Globularia s.s.
 Globularia (Globularia) aff. G. fischeri (Dall)
 Plate 15, figures 9, 17, 18
 Moderately large, weakly shouldered, greatly inflated. Spire low, turreted. A narrow sloping shelf lies between suture and shoulder. Aperture greatly expanded. Sheath moderately wide on immature specimens. Posterior part of lobe well defined on immature specimens. Umbilicus closed.
 Height (almost complete) 35.5 mm, diameter 31 mm (large figured specimen). Height 18.5 mm, diameter (incomplete) 15.5 mm (small figured specimen).
 This greatly inflated Globularia, represented by more or less incomplete and poorly preserved specimens from, the middle member of the Caimito formation of the Gatun Lake area and the Culebra formation, is closelyrelated to Globulariafscheri (Gardner, 1926-47, p. 556, pl. 59, fig. 28, 1947). G. fscheri occurs in the Chipola