GASTROPODS: TROCHIDAE TO TURRITELLIDAE


between them. Body whorl smooth. Outer lip broken ar back. Columellar lip incomplete. Umbilicus evilently very narrow, umbilical border broadly rounded. Height 2.4 mm, diameter 2.2 mm.
 This curiously sculptured species represents ain un'nown genus of the Margaritinae. The outline and thin shell suggest "Solariella" iridea Dall (1889, p. 382), IJredged by the Blake off Cape Florida at a depth of
_193 fathoms. "Solariella" iridea, however, has more inflated whorls, no axial sculpture, a faintly undulated spiral near the suture, a wider umblicus, and elongate nodes on the umbilical border. Though "Solariella" iridea was described as a variety of "Solariella" lubrica Dall, it is not closely related to that species, which is the type of the genus Suavotrochus (Dall, 1924, p. 90), described as a section of Solariella.
 Occurrence: Middle part of Gatun formation (middle Miocene), eastern area, locality 155c.
 Subfamily CALLIOSTOMATINAE
 Genus Calliostoma Swainson
 Swajesen, A treatise en mnalaelegy, p. 351, 1840. Type (logotype, Herrmanesen, Indicis generum malacozoorum,
 v. 1, p. 154, 1846): Trochus conulus Linn6 (cited by Swainson
 as "conula Mart."), Recent, Mediterranean Sea.
 Subgenus Calliostoma s. s.
 Calliostoma (Calliostoma) metalium Woodring, n. sp.
 Plate 18, figures 12-14
 An imperforate very weakly sculptured, nonnoded, carinate callistome of medium size. Whorls rapidly enlarging, outline of spire concave. Whorls, except body whorl of mature shells near outer lip, very strongly carinated by a peripheral spiral, which is visible on spire whorls adjoining anterior suture. Three weak spirals visible on earliest preserved whorl, which is somewhat exfoliated. A few very faint spirals visible on anterior part of other spire whorls. Body whorl between suture and periphery bearing weak spirals. Base bearing faint spirals adjoining periphery and wider faint spirals adjoining columellar lip. Columellar lip everted, molded against base of shell except nar base of lip.
 Height (almost complete, but crushed) 19.5 mm, diameter (incomplete) 24 mm (type).
 Type: USNM 561430.
 Type locality: 206a (Stanford Univ. locality 2699, Caribbean coast near mouth of Rio Pina, road cut on west side of river about 90 n. west of road fork, Panamd; same locality as USGS 16937), Chagres sandstone.
 Though the type is somewhat crushed and evidently is immature, the characters of this weakly sculptured, nonnoded, carinate species are well defined. Much of the type is more or less exfoliated, but even unex-


foliated patches are very weakly sculptured, aside from the strong peripheral spiral. That the type is not mature and that the peripheral spiral is reduced near the outer lip of mature shells are shown by an exfoliated body whorl fragment from the type locality-the only specimen other than that illustrated. This fragment indicates a body-whorl diameter of at least 30 millimeters.
 In outline of spire, strongly carinate periphery, and almost smooth base, Calliostoma metalium is allied to C. aurora Dall (1889, p. 366, pl. 37, fig. 2), dredged at a depth of 140 fathoms off Barbados. (Dall also recorded a fragment from a depth of 576 fathoms.) C. metalium, however, lacks the noded spirals of C. aurora and the basal spirals of the fossil are even weaker.
 Occurrence: Chagres sandstone (early Pliocene), localities 206, 206a.
 Subgenus leiotrochus Conrad
Conrad, Acad. Nat. Sci. Philadelphia Proc., p. 288, 1862. Type (monotype): Leiotrochus distant Conrad, Miocene,
 Maryland.
 Assignment of Calliostoma eremum to Leiotrochus has the advantage of indicating that this species has an umbilicus. It is doubtful, however, whether the strongly sculptured C. eremum and its allies are closely related to the faintly sculptured C. distans. For the characters of C. distans, reliance is placed on specimens in the U. S. National Museum from Yorktown, Virginia, labelled C. briani Conrad. According to Dall (18901903, pt. 2, p. 402, 1892), who handled specimens identified by Conrad, C. briani is C. distans. The C. distans of the Maryland Geological Survey Miocene volume (Martin, 1904, p. 258, pl. 61, fig. 6) is imperforate and has moderately strong sculpture. Evidently it is not C. distans, as it does not agree with Conrad's description.
 As suggested by Gardner (1926-47, p. 619-620, 1947), a more natural grouping of perforate and imperforate species of Calliostoma may possibly be gained through a study of the development of the sculpture.
 Calliostoma (Leiotrochus) eremum Woodring, n. sp.
 Plate 22, figures 3,5
 A perforate calliostome of medium size. Whorls of spire slightly inflated, body whorl strongly inflated. Sculpture of spire whorls and of body whorl between periphery and suture consisting of strongly noded. primary spirals (3 on earliest preserved whorl, 5 to 6 on penult, and 9 to 12 on body whorl). A weakly noded secondary spiral in some interspaces. On late whorls some secondary spirals are transformed into primaries by becoming wider and more strongly noded. Base sculptured with 10 or 11 primary spirals. A


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