GASTROPODS: TROCHIDAE TO TURRITELLIDAE


probably is to be assigned to an unnamed subgenus. As pointed out by Powell (1933, p. 165), undue emphasis on operceular characters in effecting a classification of naticids may lead to artificial alliances.
 Occurrence: Lower, middle, and upper parts of Gatun formation (middle Miocene). Lower part, locality 138. Middle part, eastern area, localities 142, 144 (incomplete, identification doubtful), 147b, 147g, 155, 155a, 155b, 155c, 157, 159; western area, localities 161a, 161c, 161d. Upper part, eastern area, localities 172, 173, 175, 176a, 177, 177a (incomplete, identification doubtful), '177b, 178. Cercado and Gurabo formations (middle Miocene), Dominican Republic. Springvale formation (late Miocene), Trinidad.
 Subgenus Naticarius Dum6ril
Dum6ril, Zoologie analytique, p. 164, 1806; genus without species. Type (monotype, Froriep, C. Dumtril's analytische Zoologie, p.
 165, 1806; quoted from Iredale, Malacol. Soc. London Proc., v. 12, p. 83, 1916): Nerita canrena Linns, Recent, West Indies.
 The status of Dumlril's names, all of which end in "arius", will not be settled without a specific ruling, for they may be interpreted in various ways. According to Opinion 148 of the International Commission on Zoological Nomenclature, issued in 1943 A generic name published as an emendation of an earlier name of the same origin and meaning is to be rejected as a synonym of the earlier name, and the type of the genus bearing the emended name is automatically the same species as the type of the genus bearing the earlier name so proposed to be emended. Dumeril's names doubtless are emendations of earlier names of the same origin and meaning. All of them can be matched with earlier names that lack the "arius" termination. He probably emended the earlier names with the Latin suffix "arius" (pertaining to) as the name of the animal; Naticarius, for example, being the name of the animal "pertaining to" the shell Natica. His statement that "notre objet 6toit de faire connoltre les animaux et non les couquilles que les revltent" supports that interpretation. In that eves-t it could be argued that the names are to be rejected on the grounds that Dumlril adopted a system that results in two names for shell-bearing mollusks. If the nasmes are to be accepted and are emendations, and therefore synonyms, is Naticarius a synonym of Natica Scopoli or of Natica Lamarck? If it is a synonym of Natica Lamarck, it is available in place of that name, which is a homoncym of Natica Scopoli. Dumesril's names, however, were not admitted to be emendations when they were proposed. They therefore may be interpreted as entirely new names dating from his or Froriep's usage, depending on whether Dumiril's usage is considered nude. For the time being the view that they are new names is arbitrarily adopted. In 1928 Naticarius was regarded as a substitute name for Natica Lamarck not Scopoli


(Woodring, 1928, p. 378). That view, which followed Iredale's (1916, p. 82) interpretation, is far fetched, but has the same nomenclatorial effect as the view adopted in the present report.
 Natica s s., or naticids having similar opercula, occur in the Eocene (Harris and Palmer, 1946-47, p. 247, pl. 29, figs. 1, 2, 1947; Wrigley, 1949, p. 11, 13, figs. 1, 2, 8-12). Naticarius, however, evidently does not antedate the late Oligocene. The late Eocene (Jackson) Natica permunda Conrad, which has been referred to Naticarius (Harris and Palmer, 1946-47, p. 246, 1947), lacks the axial grooves of that subgenus, and has a less rapidly enlarging umbilical rib and correspondingly narrower umbilical callus lobe. Naticarius is now found in western Atlantic and eastern Pacific tropical and subtropical waters. The Mediterranean N. millepunctata Lamarck has a multiribbed operculum, suggesting alliance with Naticarios, but the ribs are very narrow and the shell has a narrow usmbilical rib. This species has been erroneously assigned to Nacca Risso. An unidentified species of Naticarius occurs in tseupper part of the Bohio formation and poorly preserved fossils from the middle member of the Caimito formation in the Gatun Lake area and the Culebra formation are identified as Natica (Naticarius?) sp. They have a relatively high spire and short axial grooves adjoining the suture. Their umbilical features and opercula are unknown.
 Natica (Naticarius) stenopa Woodring, n. sp.
 Plate 20, figures 4-6
 Of lledium size, thin shelled, moderately inflated, whorls enlarging at moderate rate, spire high. Protoconch of 2)) to 3 whorls, apical whorl small. End of protoconch marked by slight change in texture of shell and beginning of sculpture. Sculpture consisting of short closely spaced retractive axial grooves, parallel to growth lines, extending from suture and ending on shoulder on later whorls. Umbilicus moderately wide, umsobilical rib rapidly enlarging, ending in a wide callus lobe, the anterior part of which is concave. A very narrow deep groove in front of umbilical rib and ucbilical callus lobe. Parietal callus smloderately thick. Opercului bearing a marginal rib and 4 or 5 wider flat ribs, all separated by deep grooves.
 Heig t 15.2 mm, diameter 14.8 mmsc (type). Height 21.5 ms, diameter 19.5 mml111 (largest specimen).
 Type: US'NM 561340; paratype, USNM 561341; paratypes Stanford Unv.
 Type locality: 177b (USGS 5854, Mouct Hope, west side of Panama Railroad near oil tanks, Canal Zone), upper part of Gatun foruatioc.
 Natica stenopa is widespread and locally common in the Gatun formation, especially abundant in te upper


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